It's actually a real motherboard.  I think hardOCP did a write-up on it.
g.
On Fri, 6 Sep 2002, Joe wrote:
     You gotta be kidding! It's not even April
Fool's Day yet!
   Joe
 At 08:14 AM 9/6/02 -0600, you wrote:
 Sufficiently retro to be interesting.
Take a look at 
http://www.aopen.com/products/mb/Pax4b-533tube1.htm. The tube
is used in an onboard audio preamp.