not a rumor. They openly admit it. Its in testing. and "coming very soon"
Im not sure if this is it in testing or just a test area for their web developers
http://beta.bittrex.com/It don't look promising, no trollbox and when I click the buy or sell wall at certain spot it wouldn't give me the total of BTC/Amount of coin, I think this option is very useful, it still don't exist like Poloniex.