I've actually done a similar one in the past, below. However... I'm going to be changing it up a fair bit to when I last did as there was a few flaws. http://www.pokebeach.com/forums/threads/trick-trump-xy-base-set-game-over-winner-revealed.121372/
Looks fun, if a little snowbally. I think a standard sealed league format with trading allowed would be a better starting point, since ante rules tend to just make it easier for the winners to keep on winning.