Three terations of the RV670 are coming this year and at least one is planned for 2008. The top one in this year is called Radeon HD 2950XT, the runner up is HD 2950PRO while the last one is called HD 2950GT.
The RV670 is a 55 nanometre chip but at a 600MHz clock and the whole card will have an 80W TDP. This is enough to help get rid of the power connector on the card but for the safety reasons we believe that ATI will include one.
PCIe 2.0 motherboards might help you get away without the 2x3 power connector but this is still to early to say.