http://www.amd.com/us/products/desktop/graphics/oem-solutions/Pages/oem-solutions.aspx
AMD has listed five more on their site: Radeon HD 7670, 7570, 7470, 7450, and 7350. But look at the specs: they're a Radeon HD 6670, 6570, 6450, 6450 (again!), and 5450, respectively.
I didn't like the 5770 and 5750 becoming the 6770 and 6750, respectively. But there you could at least make the case that they were still fairly modern cards. Not so with renaming 40 nm cards into a 28 nm lineup. The older cards also lack DirectX 11.1 support, PowerTune, and some other modern features that the "real" 7000 series cards will bring.
So far, these are still only OEM cards. So you'll see companies like HP try to convince their customers that it really is a 7000 series card, but they won't show up at New Egg. Or at least, not yet. But the 6770 and 6750 started out as OEM cards before ending up available to everyone under the new name.
So why is AMD doing this? My guess is that Southern Islands doesn't contain any true low end GPU chips, and their business model is to keep selling 40 nm GPU chips to fill the low end. If even the bottom bin of Cape Verde is a $100+ card, then a lot of people simply aren't going to pay that. The charitable explanation is that renaming cards into the 7000 series indicates that this is what AMD has for such customers in 2012.
So why not make new GPUs at the low end with the modern features? TSMC's 28 nm process is in high demand, but still has limited capacity, so they're charging a lot per wafer. Higher end cards have to move to the 28 nm process for a variety of reasons. For lower end cards, it would be nice, but isn't as critical. So AMD decided to move the higher end cards to 28 nm and keep the lower end at 40 nm for now.
I'd expect that AMD will eventually launch some lower end 28 nm cards, but that might have to wait for the Radeon HD 8000 series. By then, TSMC's 28 nm HPL process node should be mature and have plenty of capacity.
Now we just wait to see if Nvidia renames their old cards into a new series, too. Kepler is still a while off, so there isn't yet a need to rebrand the lower end Fermi cards into a Kepler series for the same reasons that AMD is doing rebrands. But then, Nvidia's GeForce 100 and 300 series cards were pure rebrands, so I wouldn't be surprised if the 600 series ended up that way, too. Even the GeForce 500 series cards were a mere respin.