I would say that Plague, Vikings and my neighbour starting with K (KSQR?) are probably your best choices at the moment. Plague has a rather important Empire, but size can be a problem; Vikings are a force to reckon with, but their economy has been weakened; and the Imperium is an isolated Empire, which can be an asset or its death warrant.
I wouldn't worry JLS: you *will* have a spot waiting for you in one week. I cannot say anything about the state of said Empire though.
The problem with starting a new game would be to find players willing to play with Proportions to begin with, since Proportions requires more time than the stock game to reach the interesting stages of the game. If there is enough interest, what about doing something like a scenario start? A very nice game owner with too much time on his hands would play all Empires and develop their economy a bit before gamestart (an example of it would be the "A House Divided" game). Obviously, it can only be done with few players, and a volunteer for the very boring setup phase.