I got some carbon wheels from a chinese seller on ebay. Took about 6 weeks to arrive, but he said that he was having trouble with his supplier and it didnt usually take that long.
Wheels look fairly well built, had a good look over them when they arrived and couldnt see any obvious defects. I only use them for races so they have only been on my bike for about 100 miles so far. Tbh, i wasnt expecting them to be great, but i havnt had any problems with them. Hit a fairly big pothole during the race but they still run perfectly true.
I read as many forum threads about chinese stuff as i could before i bought them, theres lots of info out there. People say that you can get better prices on alibaba if your careful. I chose ebay for a bit more security tho.