The Tech Report did some research and reports the new ATI Radeon HD 5850 is nowhere to be found. The same was true for the Radeon HD 5870 last week, but availability of these cards has dramatically improved over the last couple of days.
Newegg started carrying two Radeon HD 5850 models from XFX and HIS last night, but both cards are now out of stock. TigerDirect, ZipZoomFly, and NCIXUS are all in similar situations, with cards listed but unavailable. The picture is essentially the same north of the border at NCIX, too.
On the upside, while Radeon HD 5870 cards were hard to come by last week, availability seems to have improved quite dramatically over the past few days.