A new version of FBA4PSP for emulating CAVE machines has been released. This was released a couple of months ago but i happened to stumble upon it while searching for FBA4PSP v12.4. There is an unsigned version for those wanting to play this on firmware 5.00 M33 and 5.50 Gen, There is also a signed version for 6.XX firmwares available. I have tested this myself on a PSP-1000 5.00 m33-6, 5.50 GEN-D FULL and 6.39 ME-5. The games tested and working are: GUWANGE, ESPGALUDA, DODONPACHI, DODONPACHI 3, ES.PRA.DE, MAZINGER Z, METAMOQESTER as well as other fighting games. There is a tiny bit of slowdown i'd say 95-98 FPS with sound so play around with the frameskip a bit and set the rotate vertical games to OFF if playing a shooter With the settings just right you won't notice any slowdown with full sound once you really get into the game. It almost felt like i was emulating this on my desktop. The link to the download page follows:
FBA4PSP 20110319 - EmuCR
Please note that DODONPACHI 2 BEE STORM is not emulated in this release as it is not a CAVE hardware game, it is a PGM hardware game. It may need the PGM bios file in the rom directory but i have not tested or confirmed this in any way.