I never did the '2 rear facing car seats' thing when I had my EX35. When I had the rear facing infant carrier, I had a bit of trouble fitting in the seat in front of it. Our eldest child on the other hand was forward facing in a booster for as long as we had the car.
Since my kids are past that stage, I haven't kept up with the carseat models currently on the market. But if you do a quick google search for "car seats for small cars", it should get you a list or two of the smaller models out there that might work for you. Also check out the discussion forums on car-seat.org.
There are a few threads that briefly touch upon the topic of carseats here, though I don't recall any mention of two rear facing carseats.
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