As for the previous "legal" advise... I wouldn't be so sure MS would get mad about this at all. Who do you think most likely leaked it?
I'm currently testing Windows 7 Beta, (NOT WinMo 7) and I did await the "official" release. However a leaked version mysteriously appeared online about 3-4 months before it was put up by MS on TechNet. Word on the internet was that MS leaked it on purpose to take advantage of the work and debugging that was done for them for FREE by developers all around the world.
Same thing most likely applies here. It was leaked by someone... most likely to be MS since that would be where it got it's beginning, and has been until it leaked.
Why not dump it out on the internet? Let the guys at PPCGeeks, XDA, and the like, fix and debug the thing and repost? Cut's out a lot of cost, and a lot of paid man-hours at MS to let people here do the work.
Maybe, just maybe, MS knows EXACTLY what they're doing... dropping the project in the hands of people that are in some cases, more educated than the developers that work for them. Anyone agree on this?