No. I had an Abit A8N-SLI in a LianLi PC-v1200 with the FSB at 250 for 3 months, with 7800gtx SLI, and I also had an Abit AN8-32X in the same case at the same 250fsb. No problems.
I am wondering about this too. I heard that the heatpipes could cause the southbridge to cook if the mobo was upside down. I have a lian-li that I have modded to be upside down, so it would be nice if I could know more about the situation before I go and buy something that wont work in my case.