Technically any race can be any class, however, due to the fact that some race/class combos are such a small minority, if they even exist at all, what with cultural conflicts, that there simply aren't enough to warrant a race/class combo. Here are the races that fit into that Category
Humans (They're not bad with technology, just not good enough to be Tinkers)
Worgen (See above reasoning)
Pandaren (The only "Technology" Pandaren even know of, is Mogu Technology, which even they didn't know how to use properly, because it was titan technology)
Orcs (The only thing Technological Orcs make are Siege Engines and Crude ships)
Sorry Teriz, the outcome isn't likely.