I mentioned SVN's MIME support before. It offers other possibilities too. Will track some here.
Heres my tag cloud: http://del.icio.us/fox_conor/svn_mime
One in particular (redbook iirc?) is really cool, it says properties can be binary as well as text. COuld be a good way to attach MP3s etc to base file.
ooooh, conor fox.