liberty flights has the ce2 normal size and xl size and they have them for 510/ego and 2 or 3 other models (sold out at the moment but according to the live chat should be in stock later today or tomorrow they recived them from customs and just need to sort them out as they are all in one big box)
ivapour has them for the ego and they are in stock
those to sellers are both in the UK, dont know any sellers in US thou