Dual Xeon Motherboard and Processor Suggestions For Lion

I want to build a dual processor desktop machine that can run OS X Lion as one of a bunch of other operating systems. The idea is to buy a Mac-compatible motherboard, two physical Xeon processors each of six cores, gobs of memory (ECC if it must be) and probably at least one Apple Thunderbolt display. Then I want to run a bunch of virtual operating systems: OS X Lion as a virtual machine, Fedora, FreeBSD, Windows 7...you get the idea.

Does anyone have advice for doing this? I can't find a "CustoMac" build that does dual or quad Xeons. After working with a friend's dual Xeon Windows 7 computer, I'm now convinced this is what I want for my wife's new computer, but I want to be able to use it as well from my own office in the next room. Because of her, it is very important to have the choice of both OS X Lion and Windows 7.

What dual Xeon motherboards will work? I see several interesting SuperMicro boards that look good...but is SuperMicro a good choice?

Is there a "Thunderbolt" adapter card I can use to connect an Apple Thunderbolt Display to it?

Does Xeon processor selection matter? Of course I want to buy the two fastest I can afford.

What is the most Mac-friendly virtualization software? Should I get VMWare, or is Fedora's virtualization good enough as a host?

Thanks for suggestions and advice.

Bob Cochran