www.foryourears.com seems to be well on its way with the whole online download thing and its mainly techno and breaks oriented.
I still call for the database idea that links releases to where they are available online (and physically). I would do it myself but I'm no net coding guru... The internet can be used so well for cataloging and hunting down music...
Is anyone chummy with the guys who run www.discogs.com?
They have everything in place for such a thing. It would only be a matter of taking the base code, sexing it up and changing a bit of text around. Information is contributed by label owners, shop owners and anyone who joins up then gets verified by the mods before being posted online.
Once the structure is in place, it doesn't take much to add an entry. A couple of minutes tops. It would consist of non hyped/promotional release info (such as name, tracks, date released, credits etc) and store locations/urls.