Although it's neither feat nor psionic power, the effect you want's available as a low-priced magic item and a mid-level spell.
The Magic Item
The Web site Athas.org teeters on the extreme edge of official, saying that it
is recognized by WotC as the Official Dark Sun site on the internet. Content created on the official website is considered to be derivative work (as it is based on the intellectual property owned by Wizards of the Coast). This means that fan-created add-ons (such as new net books, adventures, etc.) are jointly owned by both Wizards of the Coast and the creator; neither can do anything outside the official website without the permission of the other. [sic]
Thus in the unlikely event the DM can be convinced to allow material from Athas.org (Comments' experiences say most DMs won't), the Athasian Emporium contains the
Third Eye Long Touch
The wearer of this kind of third eye [MIC 140] can use his touch attacks as if they were ranged touch attacks with a 30-foot range increment. It does not actually grant reach, and so does not help provide a flanking bonus or allow the wearer to make attacks of opportunity at any range greater than normal. The wearer uses his normal melee attack bonuses and normally affects the target with the effect of his touch if it hits, though the target of the attacks can benefit from cover or concealment.
Faint telekinesis; ML 1st; Craft Universal Item, far hand; Price 2,000 Cp.
The notation Cp--not to be confused with cp meaning copper pieces--stands for ceramic pieces, the Dark Sun campaign setting's equivalent to gold pieces. (Yes, in the Dark Sun campaign setting, the most commonly encountered currency isn't mined but baked. Just go with it.)
On the right face, this is a ridiculously useful item at a very low price.
The Spell
The 5th-level Sor/Wiz spell greater spectral hand [necro] (Dragon #303 36-7) is like the 2nd-level Sor/Wiz spell spectral hand [necro] (PH 282) except that "the hand can deliver any touch range spell of 6th-level or lower. In addition, if [the caster has] a supernatural effect tied to [his] touch, such as a paralyzing touch, the hand can deliver that effect as well." Further, the hand's 3d4 hp total is subtracted from the caster's own. (A non-greater yet still spectral hand has, instead, its 1d4 hp subtracted from its creator's hp.)
Just this far from fitting into a wand, one would have to cram the spell into a custom staff of greater spectral hand (34,050 gp; 4 lbs.) (50 charges) or talk to the DM about a different, even more custom magic item.
This is, admittedly, not a ranged touch attack and instead a means to use a touch attack at range, which may be close enough.
Duskblade 13/Crusader 1/Jade Phoenix Mage 6 seems to me to be much superior to Duskblade 20. You hit the really big duskblade class feature and retain your highest-level spells.
The issue is timing. The best levels to take Crusader are 5th, 9th, or 13th. Coincidentally, however, 5th, 9th, and 13th are also the levels where it is most painful to have a single level of crusader rather than being a single-classed duskblade, as those are the levels at which you get new levels of spells (and full-attack arcane channeling, in the case of 13th). You have two competing goals: get the next spell level (and full-attack arcane channeling) as soon as possible, while having maneuvers for as long as possible, since they are useful.
Therefore, I recommend taking the crusader level at 6th, 10th, or 14th; that is, I’d take the next spell level first, rather than the maneuvers. Here’s a breakdown of each option:
Duskblade 5/Crusader 1
You can take 2nd-level maneuvers with your first five maneuvers. This means, primarily, that you will have mountain hammer for the longest possible time, which is awesome. Other than that, though, you’ll probably still take a number of 1st-level maneuvers.
Duskblade 9/Crusader 1
You can take 3rd-level maneuvers and stances with your initial set; you can skip crusader’s strike for revitalizing strike, you can still take mountain hammer, and the amazing white raven tactics is available to you. Thicket of blades opens up as an interesting stance option; martial spirit is pretty small at these levels, and thicket of blades greatly improves your presence on the battlefield.
Duskblade 13/Crusader 1
Clearly if you haven’t taken crusader by this point, you should. Duskblade has little to offer, so you lose almost nothing at this point. The disadvantage of waiting this long is that you haven’t had maneuvers at all until this point. The advantage, on top of duskblade features ASAP, is divine surge, an excellent offensive maneuver.
The Awkward Bit
OK, so now that we’ve covered how to do it, there’s one other thing to consider: you cannot use arcane channeling and a martial strike at the same time. Arcane channeling requires a standard action attack or a full-attack, so the attack(s) you get from a strike don’t count. This makes strikes massively less useful to you than they would be to others. A boost or counter heavy selection of maneuvers solves this issue; you could do pretty well with defensive rebuke, shield block, and white raven tactics. But missing out on fantastic options like mountain hammer, tactical strike, the various healing strikes, and divine surge is a disappointment.
It also means you don’t have especially great mobility. You have invested 13 levels in duskblade to allow you to full-attack with spells, so you really do want to be making full-attacks. Crusader doesn’t help with that. Swordsage or warblade would help a little, since Tiger Claw is pretty good at that (sudden leap, arguably pouncing charge), but cleric for Travel Devotion or barbarian for Lion Spirit Totem (Pounce) might be better. Those options don’t lead into a great prestige class like jade phoenix mage, but they still might be better options.
The Other Thing
Finally, item-based healing is generally sufficient in 3.5. In-combat healing is rarely an optimal strategy, barring emergencies; the crusader is far better at this than other classes, but you shouldn’t usually need it. The aura you describe all-but-eliminates the worst emergencies, too. Wands and healing belts are quite sufficient for out-of-combat healing. As Jeor Mattan mentioned in comments, the real draw of actually having a cleric is the various options he or she would provide for removing status conditions, since items have HP-healing pretty much covered (and until you get heal, clerics’ HP-healing spells are pretty poor), and crusaders don’t cover that at all.
This is another situation where a level of cleric may be more useful to you: it would allow you to use wands of any cleric spells you like, with no Use Magic Device check. That will cover a lot your needs.
Best Answer
If you are open to a 3rd party source, may I suggest making a slight alteration to the existing feat Reach Spell and convert it into a new feat named "Close Spell". Which basically is a feat that does the opposite of what you are asking for. If Dragon Magazine is legal, I couldn't imagine that a feat like this would cause any qualms with the group/DM.