Not a straight forward easy  way to do this ootb but you could do it via a
Data View Web Part using FrontPage...

Yup....tried that too. The problem is that the data  View web part
doesn't present the data to the subsite the way that a list  does. The
team members can't update their information and, more importantly, I
can't use the data to populate lookups in other lists  or link
webparts. If I could get the list in a subsite to pick up the data
from the parent, I'd be set.

I don't suppose that this is one of those things where the answer
is "use Portal Server and your worries go away" is it?

On our portal a have a Contact list  for all team site  administrators. I
created views of the Contact list based on the team sites. On each of the
team sites  a put a link to the appropriate view of the portal Conatact list.

In your case you could add a custom field to the Contact list that
identifies the site/subsite,e.g. Site Field conatins
"/sites/sitename/sitename/...", that the individual belongs to and then
create views based on that field. then on the site/subsite put a link to the
appropriate view.

Unfortunately, that just navigates you away from the subsite. The
look/feel and nav structure of the subsite is lost and the data  isn't
actually available in the subsite. So you can't do things like
populate lookups or link other webparts.

I've tried changing the CLSIDs for the list  data sources, but the
data isn't available outside of the originating site  and I get "list
not available"

I've even picked around in the database to see if I could just create
duplicate lists  in each site and use DB Triggers to keep the data in
sync. No such luck.

The inability to see lists across sites  seems like a configurable
sort of thing. I can't imagine that it's an inherent limitation of
the architecture.

WSS sites  are designed as independant entities. You can probably write a web
application that performs appropriate impersonation that reads the list(s).
Then you can put that app;lication in a page Viewer Web Part. But you will
ahave to put the application on each team site.