This seems cool. There is some stuff that Nick Kew and Jim Ley did on making
checksums of parts of documents - so you could have a checksum over
everything except the metadata, if you don't already have that.
Dealing with things that move around is just a pain. Which is why cool URI's
don't change. (On the other hand not having a high-bandwidth server issued
free at birth is a pain too...)
I'd be interested in pointing people to this stuff from a W3C project if