Well no, blame falls squarely at AMD for canning the 5850/70's, to hoard all the chips for the 5970's, its a disgrace, 2x 5800's on each of those, could have got shot of a lot of back orders from here. :/
I heard they are cherry picking the best and most efficient 5870s aswell for the 5970s to keep it below the 300W allowed max power usage aswell.
That could mean the current batch of 5870 all run slightly less efficient than the release parts, which could effect overclocking etc. With the price increase aswell, early adopters are for once the lucky ones!
It could all be rumour though, but it seems to be a realistic assumption.