Can someone pick a exchange please, so we can send 2000 emails for that pair.
I know it's not everyone's favorite but I vote cryptsy
bittrex would be my vote, but ill go back to cryptsy if this happens.
bittrex has no usd markets, right?
i'll also go with cryptsy.
alcurex.org would also be an option, no volume there what so ever, but they have usd markets. They also call microCoin a top crypto currency. shouldn't be too hard to convince them.

One of the best exchanges IMO is BTC-E. I don't know their policy of accepting alts - they have very few alts and no changes their since a year or two.
However they also have some alts that are not that good - Feathercoin and Terracoin... Maybe they could be open to trade XC/USD. But some officials of XC should ask them ...