Wow this thread is full of people quick to criticize the OP's ideas. Fair enough, a system builder is very unlikely to make a lot of money, and the idea of overclocking for a 'large' company may be a pipedream, but there are overclocking and system builder jobs out there, and not everything in life is about making as much money as possible.
RBCustoms from these forums used to work building custom computers (Although he does have 1337 airbrush skills), and I have spoken to several other people who's day job involves building custom computers and overclocking them etc. So the jobs do exist, although they are few and far between and may require some other skills (airbrushing, sales etc).
Having said that though, the OP can always aim towards that sort of job if that is what he wants and is aware that it is likely to be low paid. You never know, it may end up being a doorway into something he likes better and pays more. If IT really is the area that the OP wants to go into then looking into the Microsoft, Cisco, CompTIA and even Apple qualifications may be a way of getting his foot in the door.