Well, I finally managed to score a code, but unfortunately it was for the japanese version.

lol Oh well, beggers can't be choosers.
It's still just as playable (although japanese voice overs aren't helping in the video tutorials, pretty much all the text is in english). One thing is for sure, I'll be buying this game.
My impressions so far of the japanese beta: It hasn't exceeded my expectations (because with all the hype they were pretty damn high), but it definitely lived up to them. The "story" mode stages are pretty fun, a little more than I expected to be honest, and great inspiration for creation (where this game shines). I would love to be able to tweak Sackboy's movements, as he's a little slower, "floatier", and doesn't quite have enough height on his jumps than I'd like (this can easily be seen in videos).
Playing the tutorials are pretty much necessary to design anything remotely complex, but so far it hasn't been overly complicated (confusing at times, but that might be cleared up with an english speaking announcer). The tutorials themselves can be fun, as it's almost like playing a puzzle in a game (granted they are mostly simple/easy and it might be a little more tricky for me without comprehending japanese).
I've been able to create just about everything I've wanted to so far, but some concessions have to be made at times. I have yet to find a way to make cardboard enemies harmful without adding dangers to them (fire, electricity, gas, explosives or spikes). So my homeade goomba has spikes on its sides and my rolling pacman of doom has to be an evil pacman of flames rather than the yellow icon we all know.
Being able to give away creations in your stages is by far the best thing about the create a stage, especially considering you have the option to sort of copyright protect it (items can only be unlocked by others if they play your stage, if you so choose to make that option). Then they can import your creations into their stages. I have little doubt that some great super mario knock-off stages and baddies can be made (hell, my goomba looks really good considering what I have to work with at this point). To create massive levels, it will take a team effort run much like a business or project, with coordination and planning. It's not a quick process, but it's pretty dang fun. I could see a group of people getting together and splitting up tasks by enemies, portions of stages, contraptions and project managing (tying everything together). I personally would love to be a part of a team like this if it's run in the right way (fun, laid back).
The sackboy customizing is a tad more limiting than I'd hoped (more like playing dress up with dolls than creating your own look, very cookie cutter), but if they had tons of costumes in the full version it should be good enough. Using the PSEye is pretty cool, and I could see it being useful to get that added touch of realism. So far I've used it to stick myself and the bat signal up in the game (the two closest things to me at the time). The resolution looks pretty crappy at times, which I'm sure was done intentionally to limit the file size.
Basically this game is great for someone with a mind like my own (very much into physics). Honestly this could be used as a teaching tool in basic physics classes if they didn't dumb down the science (I'd like to see speed, forces and spring constants, intead they give you a scaler representation), but I understand that was necessary to open the game up to all people/backgrounds.
I will be pre-ordering my copy soon

, and continue wasting my efforts on the japanese version (everything I create from now til Fri will be gone when I buy the game

).