In my opinion Pi and Little Big Planet are a perfect match! The message of creativity and openness from LBP is a perfect compliment to the Raspberry Pi philosophy! But, from a more practical point of view it probably won't happen, but not impossible if I understand some of the things in this post right. You say Eben (the great and powerful) knows somebody important involved with LBP, and Pi already has a pretty good relationship with Sony (they put Pi together), it might happen, but unlikely. First, the Pi foundation would have to take the time to try and make it happen, then the devs would have to be willing to port it to Pi, and finally Sony would have to be okay with putting a Playstation exclusive on another platform, which is all pretty unlikely. Emulating the PSP is the thing I think is the most likely way this would happen, but maybe a little far off. First someone would have to have enough interest and skill to do such a thing, but I'm sure it's possible. A quick hardware comparison:
700mhz armv6 single core |333Mhz dual core mips processor, one core dedicated to OS, usually . | underclocked to 222Mhz to save power
512 MB ram shared between gpu and cpu |32Mb ram, 64 in slim version with 32 dedicated to UMD cache, 2Mb for graphics
videocore IV ~25M polys a second |gpu ~30M polys a second
The polys a second benchmark is generally not a very good indicator of power, so the videocore probably has a lot of extra stuff for processing that the PSP doesn't, and I think a well optimized emulator could do very nicely on the PI. Anyway, that was a little off topic, but I would love to see LBP on Pi! That would be even better than Minecraft! Or better yet, LBP Minecraft style!