If you like trek try this link for a huge forum over at Daz dedicated to Trek stuff with lots of freebies

http://forum.daz3d.com/viewtopic.php?t=131337&highlight=trek

You can also import models from games and convert them to .obj ( which Daz can use )  using a free program called nifscope.

One game site for models:
http://bridgecommander.filefront.com/ 
Not all of them convert but a high percentage do eg see my  NX-01 in my gallery image below

http://www.renderosity.com/mod/gallery/full.php?image_id=1950514