There's probably significant value in building something that works like a DELL build your own PC tool, but pulls in components from all the sites over the net, then puts together the shopping cart for you:
1) Takes you through each component choice: memory, case, cd/dvd, hd,etc.
2) As you choose the size for each one. 1tb hd? 8gb of ram?, it pulls together the lowest price, and sets up the shopping cart for you.
Problem I see- getting orders from multiple vendors.