I once created a MTG game that would use the cards as spells and could be based on the Magic world of Dominera, if you want a map though, that is a bit harder to come by.
If anyone wants to hear about that MTG game I adapted it to the d20 system and is really fun at least I think so. The only problem is that literally it is like playing a magic game each battle system, so it can be a bit long hehe, but that was half the fun. Also battling wasn't as much the point in the game, while the spells were there to aid the players, they just tried to use them in more creative ways.
I toyed with making a MTG conversion. But after i started compiling a list of possible classes/prestige classes/races/spells/magic items and everything else, the project seemed so staggering i didn't continue!! :0