We got word that Xploren's released a new version of his well-kn own Black32 XMB Theme. It's got some new features, and he does note a fix to the current problem of it disabling PSX emulators.

Here's what he had to say about Black32 XMB Theme - encore 4:

Black32 has been updated to encore4 [Mar.5th]. It now has new Game and Photo menu loading icons, the Small Italics font, choices between no opening/gameboot logo, and new Black Rhizura icons by innercy. More updates are on the way.

The same precautions apply to this version though. Check the readme, remember that this can brick PSPs, and know that you're installing this at your own risk. Note that this also won't work with 3.10 OEs and you should be okay. As for taking care of that PSX emulation problem, you can also visit the second PSP forum below called "Custom Coldboot + PSX Emu" for more information.