Yeah, pretty much the only way to play solo is to build two decks and play them both against each other. I sometimes test decks and combos this way.
I'm doing that a lot, too. It's one step in tuning a deck. It takes a bit of training to blank out knowledge of a player's hand, though. Basically, you always need to evaluate the available information from the active player's viewpoint, then make a decision for the optimal move under those conditions.
You have to decide for yourself, if you consider this kind of 'playing against yourself' fun. You might be better off waiting for the Star Wars LCG or one of the other (co-op) games that support single players, e.g. Arkham Horror.