I'm not saying it's technically impossible, but we know that hasn't happened based on the released system requirements for New Vegas.
Both GeFore 6 series and X1300 Radeon and above have Shader Model 3.0 support. Since those are stated as minimum .... we can assume Shader Model 3.0 GPU is needed to run the game.
Another fact to back that up, is that FO3 in Radeon family of GPU's stated X850 as minimum.....
X850 is way more powerful, than X1300, however as you probabaly know X850 supported only SM 2.0b.....since X1300 is now the minimum (and is actually weaker than X850) we could expect, that the game:
1. will run on even weaker GPU, than X850, but
2. the weaker GPU still has to support at least Shader Model 3.0
I hope that clears this dylema for all the people who wonder, whether they can run the game