MicrostockGroup

Will the 5d2 meet the requirments of the stock sites?

yeah, it seems like you should be able to.  It will very nice to have a variety of quality glass to use.  I bought a small camcorder for stock videos recently and have been a bit frustrated with the limitations of that lens.  It would be great to have DSLR control over the aperature, focus, focal length etc.

The sound is probably pretty crapy but most stock videos don't have sound anyhow so it should still be OK.  I don't even think stockxpert accepts videos with sound.

Probably you can. But don't forget that in 90% of cases video from Nikon D90 wont be acceptable on stock (or you have to do same shot dozen of times). Canon used the same shutter technology but they say 5D solve shutter problem. We will see but don't buy it until pros approve it.
This is the main problem of shutter video on SLR camera:

http://s477.photobucket.com/albums/rr134/jamesmel9/?action=view&current=DSC_0012.flv

Dario