Thanks for the summary!
It seems to me, there is potentially enough ready to merge into 0.7 to start
the RC process right away if someone wants to... except that the first merge
will probably require rebasing everything else ;)
Next up are some changes already ACK'd for 0.7: Hearn's "pong" message (#932)
and Wladimir's Visual C++ 2010 fixes (#949). getmemorypool BIP standardization
(#936) is also ACK'd, but it might be good to wait until later in the merge
window considering its low impact and high potential for change as the BIP
gets closer to Accepted status.
any sort of high-volume bitcoind usage (such as solo mining). Some other
optimizations by Joel such as the optimized ToHex function (#562) and
Scott has a pull request for Bitcoin-Qt to behave more like other close-to-
systray applications by toggling the hide/show action (#855). He's also
contributed a patch to show miners' immature balances on the overview screen
(#837; it leaves only a blank space for non-miners). Nils, on the other hand,
has been working with a UI designer to totally remodel Bitcoin-Qt.
Coderrr has rebased his Coin Control features (#415) to the latest version.
These seem to be popular, so should probably be merged as soon as it's had proper review.
Finally, I don't know the status of Pieter's IPv6 support, but I hope it will
be ready for 0.7. Right now all I see submitted for this is support for
multiple local IPs (#829) though.