Content negotiation: add Topic Maps?

Hi,

It occurs to me that we could extend the idea of content negotiation to 
include Topic Map data describing a resource.

As an example, I have extended my Wordsworth Trust sandbox application 
so that the same URL, e.g.:

http://collections.wordsworth.org.uk/object/GRMDC.C104.15

delivers RDF if you say you want application/rdf+xml, XTM 2.0 if you say 
you want application/xtm+xml, and HTML otherwise.  (If you want to go 
directly to a specific format, add "rdf/" or "xtm/" after "object/" in 
the above URL.)

This means that the same non-information resource URL can be used for 
both RDF and XTM descriptions of that resource.  Good idea?  Bad idea?

Richard
-- 
Richard Light
XML/XSLT and Museum Information Consultancy
richard@light.demon.co.uk