> My view is that this is not a TEI-specific problem, and so the TEI
> should not come up with its own solutions.
That seems reasonable.
> <xref url="/cgi-bin/resolver?id-=FOO">
> where "resolver" is a script which looks up FOO in a database and
> redirects to the right place.
A good solution should be declarative, I think (a script might be
necessary to actually follow the link, but you shouldn't need a running
script to understand what the link refers to).
Syd's suggestion of using XIndirect seems promising. I need more time to
understand all of the implications though. Also, I'd like to adhere to a
standard, rather than to a W3C Note.