Heads up, not full table, Texas Hold 'Em has been solved. This means that, give any play, an optimal play exists and is known. It has been solved from a game theoretic perspective.
http://www.cs.ualberta.ca/~darse/Papers/IJCAI03.html
There is a theorem in Game Theory that says that any two-player game’s solution can be extended to a game of more than two players, but this extension isn’t so straightforward.
Heads up Hold 'Em is complex, but the number of options is limited enough for it to be solved by brute force. Something like full table Hold 'Em is a completely different story.
Also, Stud (and Razz, though not as much) is considered a much more complicated game than Texas Hold 'Em. I doubt anyone will be able to solve Heads Up Stud before the invention of a good Quantum Computer.