wow, this networked gameloader sounds fun It's a shame, the PS3 has so much restrictions.
It doesn't need app-sign, but unburnable media signature (just some master-disc writer capable to write bootable disc). There are a bunch other non-sony-approved bootable app for ps2 like hdloader, action-replay... etc.
But you need not forget the whole stuff is only for PS2! Even if it's work on ps3 too.