We just switched from the tiny-baby car seat (base plus seat) to the stand-alone seat (that can be rear-facing or front-facing). Our son is still 8 months old/about 20 pounds, so he's still rear-facing. The old seat was fine; the new one is REALLY tight (because it's bigger, and sits directly on the seat, instead of being raised by the base).
Moral of the story: take your car seat to the dealer and try it out. They're not all the same. I can't sit in the passenger seat anymore, and even my 5'2 wife is really cramped and often has to sit with her legs crossed in the seat because there's no room in footwell.
I don't think this is a Patriot problem...it's more of a function of how much space rear-facing seats can take up. We've had it in the other cars we've had too (except our Honda Element...that had amazing space). We're feeding our kid lots so he'll get heavy enough to face forward soon!
'07 Wrangler X Unlimited, black. Just getting started.
*SOLD*'00 TJ Sport, Solar Yellow, sailcloth top, safari/duster combo, 31x10.5 Firestone Destination A/T