Hi Chimestrike
Welcome to the forum
Best bet would be to have a look through the build logs, to give you some idea of decent machines and the work involved, then if you feel you have the required skills to take on a build give Dean(Jazzcnc) a ring and have a crack.
It would be useful if you can weld as steel is going to be the cheapest option,also you don't want to be using a router on the Z axis, far to noisy and will wreck the bearings in no time.
Good Luck
Mike