Ooh, I thought of another one. RPG Maker 4, released on the PS3. I have the third one for the PS2 and it's great for relieving that creative game making itch I occasionally get. The only real downside is, your stuck using presets for most things, and I run out of space quickly.
Releasing another iteration on the PS3, using a similar sharing system to LBP's would fix that issue.
Or, if that can't be done, then port over the Japanese version that's in the DS.
Either of those would really make me crap myself with joy.