multi-arch build: works on something complicated like the 2.4 kernel?

[Robert P. J. Day]

  i'm perusing paul's paper on multi-arch builds at

http://make.paulandlesley.org/multi-arch.html

and am wondering if that technique would work on a multi-level source
directory -- specifically, the linux 2.4 kernel.

  i can see how that approach would work fine for a single-level
directory containing the source.  does it generalize nicely to an
entire hierarchy?  (theoretically, i don't see why not, but i'm still
reading.)

rday