Botach is out, but they are the cheapest out there. They also didn't have any ETA on when more will come in, but did say they will honor that price and ship it out once it comes in. Personally, I've never had any issue with them, but then my shipping address is like 10 min away from their shop so that might make a difference.
I spoke to a rep at Surefire and they said the X300 Ultras just started to ship, so only a limited number or retailers have received them so far. She couldn't look up any stock in-hand numbers for her retailers, but just said to keep checking with them since Surefire is getting them out now.