yum arch handling

So, I'm toying around with the idea of using yum to install non-hostarch
packages into some installroot. For instance, I have a repo containing
some noarch and arm rpms. On an x86 box, given a yum.conf which only
points to that noarch+arm repo, I'd like to be able to do something
like:

  % yum -c my_yum.conf  depsolve 'somepkg'

The problem is that yum doesn't seem to want anything to do with arches
which don't make sense for the x86 host. Not even 'list' them. If I run
the yum list command, only the noarch rpms are shown.

Am I missing something? Am I crazy for even thinking about such a thing?

--Mark