I have recently purchased a second-hand Dell Dimension XPS T450.  I
would like to purchase a new case for it (a la
http://www.tigerdirect.com/sectors/extremecases/index.asp).  I have
heard that some Dell motherboards are proprietary and will not fit in
anything else but the case it was originally in.  I would like to know
if I can purchase one of the cases on the above site with confidence
that I will be able to rip the guts out of the Dimension and put them
in there.  Also, if it is possible, please list any applicable caveats
of doing so.

Specialized Case:

I own an XPS T 600 (same case different processor).  I was more than
able to move the motherboard into another case.  But I put it right
back into the original case.

Dell made that particular model very well.  The case design although
cramped, seems to keep the system cool and effectively running.

Suggestions for that specific product:

1) Go get a PowerLeap processor upgrade (about $150) that will bring
the 450Mhz processor up to a 1.4GHz Celeron www.powerleap.com

2) Add more PC100 Ram ($35 for 128, $70 for 256)

3) Add a new hard drive w/ controller card (prices will vary)

4) If you like to game replace the video card with at nVidia Geforce4
TI4200 (best bang for the buck card @ about $150)

You don't have to do any of these things, but any one of them would be
a MUCH better investment than a new case for that particular setup.

You can check prices at www.pricegrabber.com

gpfontaine,

Thank you for your comment.  The reason that I want a new case is
because I would like to put 3, 4 or more drives on the system.  The
original Dell case is made well, as you mentioned, but it appears
putting all that drive capacity in the existing case is prohibitive. 
Point well taken about the processor and memory upgrades.  I think I
will definitely take advantage of the additional memory, but since the
intended purpose for this machine is non-CPU intensive (file server,
thus the need for all those drives) I will probably keep the CPU @
450mhz.

I am glad to know that I can move this system to a new ATX form factor
case with confidence.

Thanks again for your comment.