[ale] *Serious* motherboards?

[JK]

Hi folks,

In my day-to-day work, I need to have a bunch of different systems
up and running in my software build+test environment.  Two build
machines (one XP, one Linux), at least two and sometimes three XP
servers, an XP workstation, and at least two and probably soon
three Linux servers.  One of the Linux boxes runs a real-time simulation,
which is pretty CPU- and RAM-intensive.  Another Linux box interacts
with the simulation on a once/second basis.  One of the XP machines
also interacts with the simulation once/sec, although not as intensely.
The other boxes have more interactive or I/O-bound loads.

I'm toying with the idea of having all this stuff sitting in a single 
box, though
still realized as separate virtual servers.  I think I'd need a motherboard
supporting at least 16GB of RAM, and probably a pair of dual-core CPUs.
Plus appropriate case, PS, cooling, ...

Every system I've built in the past has been made from bargain-basement
parts. :-)  I am not sure where to begin researching such high-end hardware.
Any suggestions for specific hardware I should look at,  or sites with
reviews of such things?

Thanks,

-- JK