I would love a Pd verision - but the problem with PD is that the games are not as well known as the commercial games for many reasons and therefore you are right to worry about the number of games nominated-
Perhaps it could be focussed on genres e.g. best pd platform game and get EAB members to post vidoes / screenshots of games for a month in the tread with links to where the game can be downloaded so people can play them and then vote at the end of month 2. Perhaps there could be a challenge with each game nominated e,g, quickest completion - highest score - to make it more interactive.
Just some mad ramblings but overall think it is a good idea.