Haven't seen it discussed yet, but MaxiGen of Team Gen has commented about the lack of a 6.xx Gen CFW. To make a long story short, he has a few points, as I understand it:
1) 6.xx CFW won't solve all of the problems in "catching the CFW scene up" with OFW, since Sony is employing more than simple FW number checks like before and are finally and actively combating CFW with game releases. In other words, on-the-fly decryption and whatnot is still likely to be needed, and recent iterations of 5.50 Gen have proven that a 6.xx Gen isn't necessary to get the newest games running.
2) Apparently the 6.x kernel is quite different than those that came before. According to MaxiGen, the jump from the 5.x kernel to the 6.x kernel is so significant, than most homebrew will specifically need to be re-compiled to work on a PSP running a 6.x-based CFW. He claims that the jump is even more serious/annoying/scene-dividing than the 1.5x -> 3.x kernel jump. (In other words, he believe that all homebrew games, apps, emulators, plugins, custom themes, etc. will need to be redone to work on a 6.x CFW.)
3) In light of those two points above, he feels than the features that 6.x OFWs bring to the table (SenseMe, comic book reader, direct PSN access) don't warrant the turmoil a 6.x Gen CFW would entail.
I have no idea how much of this is believable. I have no idea if some of these issues are avoidable by creating a 5.x kernel compatibility mode within a 6.x CFW. I have no idea if this is even possible, or if Team Gen is even up to the task. Just putting it out there, though.