Gaming Age yesterday posted a report that in-game Xross Media Bar support will in fact be a part of the Playstation 3 Firmware Update 2.40, which will release "sometime in June."
Reader hukeedonfonics also tipped us to the above video, which shows in-game XMB over the BioShock title screen. Comments claim a BioShock developer leaked it.
Gaming Age writes that requested features like a universal friends list, and in-game messaging will be a part of the drop, in addition to "a few rather nice surprises (*cough*soundtracks*cough*)" (their words, not mine.)
So, spread the word, and we'll hopefully have more on this as it develops.