Mike,
Given your bass management requirements - If you can stretch to the Lexicon MC-12B - my advice would be "jut do it". I have researched about 15 HT processors extensively and the MC8 and MC-12's capabilities in bass handling are outstanding. With 3 DSPs plus an "extra" signal processor - it has the cycles to move bass from anywhere to anywhere and support lots of channels, including 3 independent sub channels, and filters that allow bass to be redirected from small speakers to large and then to subs. Built like a battleship - regularly upgraded, the Lexicon MC-12 is the reference HT processor for many magazines and has lots of fanatically loyal owners.
The only other processor that I am aware of that comes close for your bass management needs is the Parasound Halo C1 or C2 with it's 4 extra programmable channels that can do bass redirection (or any other type of signal redirection). Also (apparently) very nice
Geoff