It is well known that BIOS v2.30, present in most of the newest PSTwos (SCPH-900xx), blocks the loophole that allowed FMCB to run in the first place. So these consoles are, as of now, incapable of running FMCB (or any other homebrew) without the help from Swap Magic or other similar solution.
I can imagine that some of the devs are probably busy looking for some new exploit. Yesterday something occurred to me. I haven't seen this possibility mentioned anywhere, although I suppose that some dev has probably figured it out already. But just in case, here it goes.
The idea, basically, would be to test whether the PS2 browser has some kind of weakness in the code that reads the directory of the MC. (I mean, if you start the console without a disc or with the tray open, it has two options, "Browser" and "System Configuration"; if you press X twice, it will take you to a listing of the contents of the memory card). I have another (modded) PS2, of an older revision, and I remember that the MC got corrupted somehow and the console would lock up when accessing the card. And it was probably not due to some hardware failure, since we reformatted the card and it has been working perfectly ever since. So there is (or was, at least) some ungraceful error handling in that part of the code.
What I was thinking is something similar in principle to the Zelda exploit on the Wii: craft a MC save which looks legitimate to the PS2, but that has some kind of anomalous data (ie. a very large title of the game, a specially crafted icon, something) which could trigger some (as of yet undiscovered, I think) buffer overflow in the MC-listing routines in the BIOS. Then, by opening the crafted savegame (or, maybe, just listing the MC contents), an .elf could be (hopefully) launched. Step 1, find buffer overflow; step 3, profit
It would not be as elegant as pre-2.30 FMCB, of course, but still easy. Open tray, power up, X, X, X, there you go.
Of course, it is just an idea, probably crazy, probably impractical, probably not original. Feel free to flame me
Now, unfortunately I don't really have the know-how to tinker with this (I have a 90004, so I would at least be able to legally obtain my BIOS and have a look at it), other than as a help tester. And I'd be in favor of donating $20 or something towards buying a 9000x for the developers to tinker with , but, of course, only if they really are in the position (and want to) try their hand at this task.