Hi Daniel,
Sounds like you are looking to do the same upgrade as I fancy, D3000-D7000, I almost convinced myself that I would step up to a D90, but I think that I may not be happy with it when I want the D7000 really.
As far as buying one is concerned I would prefer to pay a bit extra and buy within the UK to be sure of warranty issues, like to deal in readies, so may have to be local-ish, would be happy to buy off any that are associated with this forum(if cash payment could be arranged). As far as it goes with getting hold of one 2nd hand, I would be surprised if they start coming up this quickly, but who know's!
Jon