Has anyone here thought of using Shuttle's KPC as a base for running smoothwall 3.0?  Are there any special considerations anyone can think of in doing this?  Thanks a lot!

It should work fine, may even be a bit of an overkill for Smoothwall since the hardware requirments are so minimal.  You could even use something like this and save some cash:  
 
http://www.geeks.com/details.asp?i [...] YL&cat=MBB
 
If you do go with the shuttle or the above system make sure to pick up an extra PCI NIC card since smoothwall needs at least 2 NICs.
 

Thanks for the information, I'll look into that, for it certainly might turn out to be a cheaper alternative as well as not something that I void my own warrenty on installing extras.

I've decided to go with this setup from www.geeks.com
 
1  BOXD201GLYL  Intel D201GLY SiS662 mATX MB w/Intel Celeron 215 1.33GHz CPU  1.75  
1  PM240157-DT  Enlight EN-PM2401 mATX Mini-tower Case W/300W PS (Sil/Blk)  18.00  
1  1024DDR25300-SAMSUNG  Samsung 1GB DDR2 PC2-5300 240-Pin DIMM Module Major/3rd  0.25  
 
This is minus the extra intel NIC I will get.

Nice, let us know how it turns out!