Since the PAL PS3 emulates the PS2 processor, the PS2 emulator application would need to be locked down so it doesn't have access to the whole PS3, I'm guessing this is the wall Parradox have hit, so I'm thinking there are probably other holes. Can someone add to this list of methods for installing / running code on the PS3, maybe we are looking in the wrong place...
.pkg file via store
ps3updat.pup file via store
.pup file via usb /ps3/update/ps3updat.pup
.pup file via disk
otheros.self via usb /ps3/otheros/otheros.self
otheros.bld via usb /ps3/otheros/otheros.bld
are there any other /ps3/ folders on usb that are recognised?
removing the drive and mounting it on another OS and installing files directly
There is a PS2 system file which gives access to a virtual PS2 hard drive that can be installed via .pkg from the store