I tried Deep UV. Works OK in most cases, but its $800 for Deep UV, Deep Paint, and Deep Exploration) Converting models with proper skins is time-consuming. (less time to spend on code), but can be done in most cases.

3DS -> Deep UV -> MED (import .3ds). Save as .mdl. Rinse and repeat as necessary.

The other method is manually moving/ resizing the triangles into their proper location based on the skin.