There are a number of ways to play as a construct or as a construct-controller.
3.5 Options
Being a construct
The warforged race (Eberron Campaign Setting) is by-far the best way to play as a construct. There are a few other playable-by-the-rules construct races, but each penalizes you extremely hard for the privilege. The warforged get around this by limiting the benefits you get for being a construct via the Living Construct subtype. You can get most of those benefits back with the warforged juggernaut prestige class (Eberron Campaign Setting).
You can also be human and turn yourself into a construct, though the options for doing so permanently are both very poor. The green star adept (Complete Arcane) is actually one of the most notoriously-awful prestige classes in the game (pay a lot of gold for the “privilege” of losing five levels worth of spellcasting). The renegade mastermaker (Magic of Eberron) is less bad (and also super-cool), but it’s still basically ten levels (including two that miss out on spellcasting) for the effect of “being a warforged,” when, ya know, you could just start out as a warforged. In addition to these prestige classes, there are also a number of spells that can do it temporarily, such as body of war (Spell Compendium), though a lot of these are fairly high-level spells that turn around and prevent you from casting spells.
It actually gets you the elemental type rather than the construct type, but the elemental scion of Zilargo (Magic of Eberron) deserves mention just because it turns an elemental into a freaking Gundam mobile suit.
Controlling constructs
Controlling constructs can be simply a matter of taking the Craft Constructs feat as a spellcaster; artificers actually get the ability to craft homunculi (a certain class of construct) for free at fourth level, and also get numerous other item-creation bonus feats with which they can take the full Craft Construct. In addition to these, there is the effigy master (Complete Arcane), which makes specialized constructs known as effigies to do its bidding.
Changing appendages
Warforged have items known as “warforged components.” Some of these simply slot into interfaces in their bodies, but others require some reconstruction to use. These seem quite perfect for you.
There are also construct graft options from Faiths of Eberron, which can attach warforged parts to creatures (including non-warforged), which also fits the bill.
Psychic warriors have numerous options for granting themselves natural weapons (powers like bite of the wolf, claws of the beast, etc.), or even grafting a manufactured weapon to their bodies (graft weapon power). And of course, druids and transmuters can change their bodies pretty easily, and along those lines the warshaper prestige class (Complete Warrior) can modify even just parts of its body. These could all be pretty easily fluffed as a construct that swaps out parts. Particularly the psychic warrior.
Pathfinder Options
Being a construct
A synthesist summoner effectively “merges” his eidolon with himself; the eidolon can easily be described as a construct. The Advanced Race Guide also has rules for playing a half-construct. Additionally, wyrwoods (Bestiary 4) are presented as a character race, and manage to be true constructs rather than half-constructs of another type.
Controlling a construct
Craft Construct exists in Pathfinder as well as 3.5, so that is still an option. The summoner still works pretty well, this time without the synthesist archetype.
Changing appendages
The summoner’s eidolon can vary quite a bit, which can easily be described as changing appendages. This seems like the best route to me. I’m not aware of anything equivalent to 3.5’s warforged components or construct grafting.
That said, Pathfinder has a lot of similar options for druids and transmuters as far as changing themselves go (and this is one place where Pathfinder has improved the game’s balance), and Dreamscarred Press has published a quite-well-made Pathfinder version of the psychic warrior.
Spell Research: Locate City1 Treasure
Warning: This answer/action would require DM Approval. Proceed with care.
Independent Research
A wizard also can research a spell independently, duplicating an existing spell or creating an entirely new one.
Spell research information can be found here.
Role-Playing/DM Fiat aside...
Sample spell text could be as follows:
- You sense the distance and direction to the nearest treasure trove of
a minimum size and type designated by you at the time of casting.
- For instance, you could choose to find the nearest treasure trove at
least as large as a chest, or you could choose to locate only the
nearest dragon treasure hoard.
- This spell measures the distance to the "nearest" treasure as the
minimum distance one would have to travel to reach the treasure trove
without moving through solid objects.
- For example, the caster may know that a buried treasure chest is 10
miles away northeast of his position, but is unlikely to know how
deep the treasure is buried.
Also, remember that someone, or something, probably will not like the fact that you located their stash. Dragons, for example, are pretty much extremely covetous, and dangerous to your health.
1Range: 10 miles/level. Area: 10 miles/level radius circle, centered on you
Best Answer
Yes
but it requires creativity and depends on how your GM/group handles how spells/abilities work.
For example, any spell or ability that works on creatures but not on objects [or vice versa] can be used to identify a construct creature. If you try to cast Light cantrips on every statue in the room, then the spells make each statue glow, but a construct wouldn't glow because the spell doesn't work: "Target object touched".
Since this method requires lots of spells, it's best used with cantrips/orisons/knacks or other unlimited use abilities. Non-offensive cantrip options are Guidance, Resistance, Root, Vigor, and Virtue, though these are touch spells as well.
Useful non-spell abilities can also be found among a Witch's hexes or a Kineticist's wild talents, for example, since those usually have unlimited uses per day, e.g. Scar or Foxfire. Hexes and wild talents are usually ranged and supernatural abilities, allowing them to ignore a golem's magic immunity.
Whether using any such spell or ability provokes the construct depends on your GM.