Yes! You are able to trade ISIS now on C-Cex:
https://c-cex.com/?p=isis-btcPlease keep tweeting on twitter to be added to Bittrex! We have had over 29+ retweets on one Twitter status so far! @BittrexExchange.
lol guys, don't sell so low! remember only 1.8 million coins by end of pow.. but anyway i expect price will climb once the 315 blocks are done being hashed XD