So I was looking at upgrading my unRAID and also my Media Center box and have been looking at a board from Supermicro that has IPMI built it (http://lime-technology.com/forum/index.php?topic=20086.0), but is it really possible to find an add on card that supports that? It appears to be, but I am wondering if it does, does it work just the same? Any suggestions on a card to use? Basically I want remote access all the way to the hardware level and BIOS over the Internet.

any add on card will be reliant on the motherboard's built in ability for things like remote power on and IPMI level sensors and control. Most add on cards will give you remote abilities, including BIOS because they are KVM over IP. The card might give you soft/hard reset ability as that is available on most card slots, but things like temp and fan are not. The remote management card sold by Supermicro for Supermicro boards will do great in a Supermicro server, but in an HP, not so great. The Dell card in a Dell, etc.