Oh I see it now too, hmm I dont want to post the link and get u anymore competition but is it the one thats currently at $1200? I don't know if I'd trust buying a used carbon bike on ebay for any amount of serious money. Hmm omg look at the seatpost damn thats high, how the hell did he ride the bike like that lol.
There are so many sellers on e-bay that it is impossible to make a blanket statement as to whether or not it is dodgy. Most sellers are honest, but I am sure there are some who are not. The other difficulty in buying a bicycle off e-bay is knowing whether you are getting the correct fit. If you have enough experience to know that you can make that particular bicycle fit, it is not a problem, but if you are asking newbie questions on this board, then it is a good bet that you do not have enough experience to buy a bike unseen.
If you have that kinda cash, go to the LBS and get properly fitted. It will not only make a world of difference, but will make cycling better in the long run. A properly fitted any material bike, will be better than an improperly fitted carbon bike. $2500 will get you a very sweet carbon bike.