I would suggest doing texture sets for extisting clothing , with bump, and transparency maps there is clothing that could easily become uniforms .

To make your own , you need a polygon modeller , like wings or blender (both free ) or hexagon, silo, shade , etc , which are commercial products . Since your target application is Poser you dont need the layout or rendering parts , just the modeller .

There is a cheap modeller at Daz called something like Pegasys (?)