There would be little benefit compiling from source. If you are dead set on this then you would probably be better switching do a Linux distribution that is aimed at this sort of user, such as Gentoo. This is designed around the user compiling from source and therefore would suit you better.
Ubuntu is simply a collection of open source tools put together in a way that makes it a good OS for people to use. It is not a single piece of software to be compiled. If you wanted to compile an Ubuntu system from source code you would have to discover all the pieces of software (Kernel, X windows, all other software on top of that) that Ubuntu uses and compile it yourself. Then add all the package management software such as apt on top as well.
Unless there is a good reason to attempt this, I wouldn't bother. As I said before, switch to Gentoo if you want to compile everything yourself, Ubuntu wouldn't be the first choice.