Sorry, man. I wish i knew of such a thing. I have two 280 in cf right now but thinking on purchasing 290x with dx 12 myself. I normally dont buy new gen till the cards are benched and proven.
The R9 380 and 380X are shaping up to be a slightly different revision of Hawaii. Possibly clock or memory related changes will be made, but like the 7970/280X it should remain pretty much the same. Just speculation, of course.
And contrary to many speculations about rebrands of the new 300 series cards, other talk has been about how none of the new cards will be rebrands due to investors bitching about rebrands and laying out an ultimatum.