destroyertta, for a 2-door car I think any 4-door seat is going to be problematic, if you plan to get into the rear seat much. I think a sliding track could be designed, but keep in mind the safety aspects of it. You need to make sure it's strong enough to support both a front and rear collision. If you can model them after what is on your 03 Honda, that will help with the design.
Let us know how it goes. I haven't tried to find any of the Monte Carlo seats, but my guess is they're not that hard to find.