RAM drive for compiling - is there such a thing?

Question

An answer (see below) to one of the questions right here on Stack Overflow gave me an idea for a great little piece of software that could be in

Answer 1

I wonder if you could build something like a software RAID 1 where you have a physical disk/partition as a member, and a chunk of RAM as a member.

I bet with a bit of tweaking and some really weird configuration one could get Linux to do this. I am not convinced that it would be worth the effort though.