Hacking Are there any signed PS3 apps that work like the signed PSP apps

[098v]

Like the title says I wanna know if there are any signed PS3 apps, kind of like how the PSP signed apps work, without CFW installed. If not what are some ways that I could downgrade my FW from the latest 4.46 to 3.5x if it is possible.
Thanks for the help

~098v

 

[Taik]

I don't think there's any yet, only way to downgrade is with special hardware right now but I believe the new keys (the ones after 3.55) have been dumped