I argued once before (probably a couple of years back) that it ought to be 
possible to rebuild the whole netbsd source tree starting with just a 
farily primitive set of tools (pretty much a basic compiler and not much 
else, except perhaps a make that is good enough to build our make).  All 
the tools that are needed to compile netbsd should then be compiled from 
that; doing it this way would, in principal, make it possible to build 
NetBSD from a non-NetBSD machine, starting by building a set of 
cross-tools that are then used to build the rest of the system.  I think 
it is a mistake to require that you have NetBSD-current in order to build 
NetBSD-current.

Of course, I don't have the time to put my money where my mouth is, so I 
shan't say any more on the subject.

R.