Professor plum and his solution for managing plugins (prx modules) in real-time, and by that I mean actually enabling/disabling plugins without multiple reboots (read: no rebooting at all), has just hit version 4. Now the change log is poorly translated from Japanese to English by way of Google Translate, so really I have no idea what's new; however, plum has also included the source code this time 'round, meaning if you're a developer you can see exactly how plum has accomplished this feat.
plum's Plugin Manager for PSP Custom Firmware -- enable/disable plugins in realtime, without rebooting. Source code included.
v4 CHANGELOG (TRANSLATED)
•Will respond to scroll through the · LoaderMenu, from the plug To deal with many
•But you can use the reboot_loader.prx · VSH