While deciding on seating for my HT and trying to figure out seating for 4 that would accomodate a back row of 129", I found that you can find movie theater seats from Craigslist. eBay is also a good source. I eventually found that Berkline 13175s (123" in our four seat configutation) would fit and weren't much more than new rocker theater seats, but I think if you're patient enough you can find some used seats for a bargain on Craigslist. Good luck!
Budget Home Theater:
Denon AVR-1911 Receiver, Bic V-1220 Subwoofer, Micca MB42/C Speakers, Epson 8350 Projector, Home-made ~90" 16:9 Screen, Berkline 13175