The manufacturers always have a reserve supply for repairs and RMA's , but the thing you want to consider is that if they do infact run out of cards and you really like the card and want to get another for SLI then you could be out of luck. I would go with the 570 if you can aford it.
ASUS ENGTX570 DCII/2DIS/1280MD5 GeForce GTX 570 (Fermi) 1280MB 320-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
$349.99 and a $30 rebate makes it $319.99http://www.newegg.com/Product/Product.aspx?Item=N82E16814121432
If you can fit this card then you won't have to worry about heat with the cooling solution on this video card. It's a 570 for $320 after rebate.