Thanks for the feedback guys.
Matt, check out the Kenwood KFC-X1800C speakers. Admittedly, I have not heard them personally, but from what I have heard from others, they out-perform 6-3/4's in the same price range.
Currently, I have 6-3/4 A-series Pioneers in my doors, so improving on midbass isn't a stretch and could be done by upgrading to the D-series, but the Kenwoods cost about the same and I am keeping my mind open about other options, like using 6x9's. The fact that the factory Bose are 7's has me looking more at the Kenwoods though. The system in my TB was aftermarket when I got it, but I have found no evidence that it originally had Bose.
Reprise, while I am not opposed to using the factory rear locations, they are currently disconnected as the fronts and subs are amplified and they were not. Due to the nature of headunit vs amplifier, the rears were distorting long before the fronts. Even still, I only use rear speakers for giving my kids sound when the volume is low and usually keep the fader set so that they don't mess with my front stage. Not that I am a staging purist by any stretch, but I do prefer it.
I don't think I would put subs in my doors without making completely custom panels, which I don't want to do and sound deadening the crap out of the doors.. As Xavier found out, it would turn the doors into rattle traps. I keep my map pockets empty with the exception of some small travel umbrellas, but my wife sometimes stuffs things into the passenger side one and the and the resulting vibrations drives me nuts. If I were to move some sub bass to the front, I would build a new console and find a decent 8" for there, but currently I am happy-ish with the 2 10s in the rear. I just want to improve the 80-200hz 'bump' bass in the front.