Re: Am I missing something?

[Alfred M. Szmidt]

   Why not use L4?

There is an effort to port the Hurd to L4.

   The HURD on L4 web site says the project is over.

I don't know what website you are talking about, sorry.  The Hurd
pages (http://hurd.gnu.org) have no information about Hurd/L4 since it
is still in early development.  And these are the offical pages for
whatever is concerning the Hurd project.

   So is there any hurd/l4 work going on?

Yes.  See http://sv.gnu.org/projects/hurd.

   Also: Is the gnu/mach kernel with a typical complement of drivers
   (I know that's vague, but I can't think of a way around that)
   installed small enough to fit into the L1 cache of a garden variety
   cpu module?

Doubt it, GNU Mach is around 700Mb gziped.  Nor would there be any
gain whatsoever other then by a small constant factor.