I've managed Dell servers before (real ones) and aside from a bunch of stuff to make managing them in mass easier (like DRAC), there isn't very much value in trying to retrofit one for home use.
VT-x or 24 GB of RAM support isn't exactly a hard requirement in 2014. Plus the Xeon E5410 is a 2007 chip (7 years old!) and gets it butt kicked by even a low end i3 from 2012 [0].
Plus modern systems consume less electrical power which makes running them cheaper and a PC is certainly quieter than any rack mounted server (which are designed for maximum cooling, noise be damned).
Additionally if he had purchased off-the-shelf parts he would likely have a warranty for 12 months (or more). With the eBay purchased Dell machine he not only doesn't get any warranty but ALSO Dell themselves don't even support it(!) so no firmware updates.
So while this was a fun read, it just reminds me of my more nieve days when I thought doing stuff like this was a good idea. Go over to any SysAdmin forum (e.g. spiceworks community) and they'll tell you the same thing.
[0]http://cpuboss.com/cpus/Intel-Xeon-E5410-vs-Intel-Core-i3-32...
edit: Originally linked to an 2012 i5 comparison ($180 CPU). Altered it to an 2012 i3 comparison ($100 CPU) which still out-performance the 7 year old Xeon. The $100 price tag seems a lot more comparable than a near $200 CPU. Plus the i3 supports 32 GB of RAM and VT-x (the OP's requirements).