The only tablet I've heard of that would possibly have a dedicated graphics chip is the 14" Asus Transformer Book. It was one of three products demoed by Asus last fall. However, no new as to when it will be released, or if it will even go into production. The 11.6" Asus Transformer Book was also demoed, but it does not have dedicated graphics and like the 14" version, no release date nor production date.
The 13.3" Asus Transformer Book is being released soon, but it has no dedicated graphics card. I think the price is estimated to be $1,300.00 for the Core i5 version and $1,500 for the Core i7 version.