the AMD Radeon HD 7670 OEM-only rebrand based on the same Turks GPU found in the HD 6670 card, the guys from Tomshardware.com managed to score details for the rest of the rebrand lineup. In addition to the HD 7670, the lineup includes the Radeon HD 7570, Radeon HD 7470/7450 as well as the entry-level Radeon HD 7350 card.
The Radeon HD 7570 is based on the same Turks GPU and with the same specs as the HD 6570, while the HD 7470 and the HD 7450 will be based on quite well known Caicos GPU with 160 stream processors, previously seen on the HD 6450 card. The last card in the lineup, the HD 7350, comes as a surprise as it is based on now quite old Evergreen family Cedar GPU, the same one that was happily ticking in the HD 5450 card.
The good part of the story is that these are only meant for OEMs but then again rebrands are never popular. You can check out more details here