It must be Paizo only (would help if it's in the SRD) and should be human/dwarf/elf/halforc level of power as to not have any level adjustment like goliath used to have or cost additional Race Points.
I am interested in the Powerful Build trait, secondarily in having a high Str and Con and, ideally without a penalty to Wisdom.
I am planning to add 20 levels of rage inquisitor to this bad boy!
Now a good candidate is the Half-Giant, but weirdly it is psionic and appears to have unnecessary psionic extras for my needs. I also couldn't find its RP.
The reason I want this is for my Inquisitor build simulating Diablo 3's Crusader feel.
This build would be heavily armored. It would not hit often, but it would hit like a truck. I wanted Powerful Build to get him Large armor and shield for awesome effect and a large flail to smash faces with. I don't need him to have reach and Enlarge Person has more disadvantages than advantages, such as higher number of tiles to be attacked from, lower AC, etc.
Best Answer
Sorry, this is not possible. Powerful Build is a 3.5e thing that doesn't exist in Paizo Pathfinder core (it is in some third party supplements, either deliberately or because someone doesn't pay much attention to the rules at that 3pp). The half-giant you cite is a psionic Dark Sun type half-giant from 3pp Dreamscarred Press; there's a variety of other 3pp stuff to similar effect, but that's out of scope.
You can just use a larger weapon and take the -2 to hit penalty; Paizo's iconic barbarian, Amiri, does so. You're usually not getting much of a damage boost in return so this may not be UberOptimized (tm), but if you are just looking for the awesome look and feel this is your solution.
The races that are large, like the Ogre, have pretty high RP values (RP are the Pathfinder equivalent of level adjustment, another 3.5e thing not found in Pathfinder). Size large is an explicit +7 RP option, and you say you don't want to be Large anyway, though if you are tanking for the party you may want to be subject to those attacks...
If you want reach, there's various feats and magic items that will do that. If you're looking for larger, in general "rings of enlarge person," like "rings of true strike," are disallowed as exceptions to the basic crafting rules because they're super twinky.
So - no, but you can be large, though even that comes at a cost. I'd recommend just being "big" from a description POV and using an oversized weapon. Large flail, 1d10 damage, -2 to hit, heavy steel shield, done.