My view on the Virgin Racing view is one of 2:
a) Brawn was way way way to protective of his team and way to stuborn in his deal negotiations that means he has lost both drivers, one of which being the Champion, and also the only major long term sponsor they had.
b) Merc had their claws into Brawn long long long ago and blocked any major sponsor deals that would have hindered their take over.
Personally, I think its the first in the case of the drivers, and the second in the case of Virgin.
On another note, still only 12 teams. Peter Sauber today has said the Ferrari powered Sauber C29 car for 2010 is well on target, suggesting they are gearing up for the 13th slot, but the FIA havent confirmed anything? Rumors around Toyota being bought and some other teams who didnt make the cut first time round wanting a piece of it. Be interesting to see.