The characters created from the Character Creator are indeed separate pieces and put together by the choices you choose in combining them.
The textures are stored in this folder:
Game Guru\Files\characterkit under the sub folders of the parts.
If you open one of the created characters FPE files, you will see the statements that assemble them on the fly in game.
;character creator
charactercreator = t.v:2:marine_2_artic:marine_3_artic:none:none:-1:24:19:250:236:3:-1:0:0:27:60:14:13:55:13:-1:1:0
This tells the engine which parts and which textures to combine.
The rest of the texture and mesh information is ignored in the FPE file
The polygons count for any single object is capped at 22000 right now.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit, Screen resolution 1680 x 1050.