a) Do you know of any sites that do completely custom computers, and if so, what are they. (I am aware of http://www.pugetsystems.com and from what I can tell they overprice the computers a lot, making a big prophet.)

I really enjoy building computers and was thinking of doing this, not to make loads of money and to become a giant computer manufacturer, but to have some extra money in my pocket and for the utter enjoyment.
Please let me know your opinions and thank you in advance.
-Tim