Dude You Gotta Dell !!
At the end of the day it may be easier to build one. Dell has many proprietary items (not standard) like motherboard and case.
That's not to say it can't be done - it can be. However having owned many a Dell I've taken to building my own recently.
While initially you may not save money building vice buying a Dell. If you build with future upgrades in mind - you can upgrade for a fraction of the price of buying a new Dell.