Depending on how much cutting you are willing to do (sounds like you're open to the idea) I've been a fan of how DSE makes their seat mounts. I have done it in a similar fashion and it makes for a solid mount that can be tied in to other facets of the car.
Make them from 1"x3" tube and you can adjust the height/angle to meet your needs.
http://www.detroitspeed.com/Projects...dee1969251.jpg