Tech does have some nice trails - the system I was on (which is really close to campus) has about 18 miles of stuff to ride on. Lots of bridges, skinnies, and decent single track. Link:
Tech Trails They are really well mapped too. Copper Harbor (about an hour north) has some sweet trails too I hear - I have yet to ride up there. Where are you at now that the trails aren't good?
Psyko: If you ever get up to the U.P. make sure to hit some trails in Marquette - we have some awesome stuff here. The local bike shops all do weekly rides, and I'd be willing to show you where some trails are too. Miles upon miles of great singletrack up here, and some bridges and skinnies from what I hear, although I've yet to find them. (not that i'd ride those suckers!
- belinda