I know by holding control, mousing over the bottom card in a stack, then double right clicking you can flip every card in a stack all at once. However, I can't figure out how to flip every card in my *hand* all at once. I don't want to flip them at the board as people will see them.
I agree, probably not the best solution but it is an idea. Fortunately we're not talking about a large number of cards, so it's not a huge issue or anything.