As a followup to my previous post, if you get a solid white box, you
could build a machine for $17k that will beat the two previously
listed machines pretty badly, and in a small form factor as well.
Take one of these:
http://www.aberdeeninc.com/abcatg/mb1661.htm
and throw 4 16C AMDs and 128G and a SAS RAID card in it. That'll run
you about $7k.
Then hook up one of these:
http://www.aberdeeninc.com/abcatg/xdas-jbod-1u-d.htm
with 12 15k SAS drives. That'll cost about $10k.
Note that there are plenty of white box manufacturers out there that
get good customer reviews. If Dell can give you a pretty big discount
they might be able to match the price. Don't expect them to match the
service. Generally these smaller makers know their customers very
well. For instance over the last 3 years I worked at a small shop,
and we had the same tech support and sales folk the WHOLE TIME at
Aberdeen. First name basis, knew my business, made solid recs based
on my needs.