It would probably be a more sound investment overall to get a whole new bike. Although if you are replacing nearly everything but the frame, you could accumulate all those parts for relatively cheap and then ride that frame until you find another.

If you build, you have to also consider tools-if you don't have access to all of the necessary tools, that's either more cost in a shop bill for the build or some new tools for yourself. There are hidden costs in building a bike, things that you can't foresee, but I think if you can make it monetarily feasible for yourself, building one is worth if for no other reason than to learn about your bike and to know how to fix it.