Nah, the PS3 hypervisor won't allow that... which the PSP doesn't have in the equasion. So basically once a PS3 hole is found and plugged it will be a lot more difficult to find the next one, versus just playing with Firmware decryption keys, etc.
PDX is still tight-lipped on any specific info regarding which vulnerability they are exploiting to use their own iSO Loader for obvious reasons (both competition and $ony). Until the EUR PS3 release, I'd still say the only chance for a PS3 iSO Loader would be if someone else released one. Every indication of PDX releasing one prior to that has been a firm "not gonna happen" basically.