WetWired, as far as laptops being self buildable goes, it's getting to that point. Asus has a few laptops where you order something along the lines of a bare bones kit and then get parts and stuff for it. =)
The only way to buy a new computer though is to run your own business and deal with a supplier, or work for someone who deals with a supplier and will let you order things for yourself at cost. Ah, it feels good to be somewhere in the middle instead of being the end retail customer. =)