Are you trying to run them as two separate displays or as a combined secondary display with extended horizontal pixel realty?
As far as I know, MBPs can only drive one external display, even the TB ones. I think this issue has much less to do with TB than it does with the graphics card inside the machine. The card is the limiting factor and if you want to drive a second external display, you'll need an external graphics card which currently interface with your Mac via USB. However, those cards are often times too slow, necessitating the need for the faster TB interface.
Also, while the TB standard has been in R&D for sometime under the codename Light Peak, TB was just opened to the CEM market and everyone is just starting to figure out how to incorporate the tech into their products, such as RAIDs, displays, etc. I'd expect external graphics cards with TB support to come out making their appearance in Q3 of this calendar year.