I'm just going to watch and see what comes up - I know for 3 across with 1 or more boosters, I have not had anything work well in our '05 Prius. We end up with 1 RF radian (which I am not thrilled with, it takes up too much room front to back), the RSTV, and DD's Vivo. Major pain for carpooling. Couldn't get 3 across to work with 2 convertibles and a booster (DD1 had to scoot her seat out and back each time to buckle - soooo not happening.) I'd like to find somewhere to play with parkways and proboosters and see if they are any better....
I actually have already called and complained to Toyota that the new Prius V (supposedly a microvan) probably won't hold 3 kids in the back. Only 2 sets of latch, no sliding door (not even 1!), only the front 2 seats and the rear seat (i'm pretty sure they have more seats in the back of it in Japan). What were they thinking?!?!?
I know that the MA/BLVD doesn't puzzle well opposite of the radians. The cocorro might be the best option. Haven't tried it, DD2 is still RF, but will flip FF in spring. That'll make things really fun....