Just out of curiosity, how do you earn more VGC$? (apart from betting)
In your Profile you can click on VG$ to see a balance to get an impression which action netted you how much. As I see it you get major VG-Cash for increasing your level (which is done by posting and stuff). Besides that you get VG$ for adding to the game database. And you can place more bets in the prediction league. I have old entries from 2008 with VG$ for forum activity, but this doesn't seem to be the case anymore, except the level-up bonus.
Besides that I don't know about anything, which doesn't mean there aren't other ways to net shiny VG-currency.