Just back from a singing weekend, so I'm late in responding...

It seems to me that in some ways, the resource being suggested already exists....in a 'distributed' format. That is, rather than look for way to put everything (or huge glops of 'almost' everything) in one place, we need simply a way to contact those who already have it. For entire albums, of course, CAMSCO and other commercial interests exist, but for locating the tune and basic format of some particular song you 'know' was done by Blind Harry Palms in the 30s and released on an album in the 60s, you can ask places like right here! Someone may just have it, and be able to send you a sample...or, depending on legal situations, the full song. (I have had several nice requests filled thru Mudcat, and answered a couple myself....I had a copy of Red River Dave doing "Amelia Earhart" that I recorded off radio almost 30 years ago!...not high quality, but fascinating!))

And, in the same way, there are the 'newsgroups' like alt.binaries.mp3.folk, where requests are answered every day.....Yes, of course, this requires reason and responsibilty to avoid major copyright restrictions....put simply, YOU would need to deal with what you asked for and how you used it, but haven't we all been doing that for years? Who has not made a tape of some song for a friend?

The WWW/internet is causing some major thinking about how and under what conditions to share or transmit music, and how to allow artists and distributors to have fair control over their projects, but there's no particular reason that a system that is sometimes used for illegal trading couldn't be used by honest folks for doing just what Bob Coltman is looking for.

Right now, there are some songs from The McCalmans, a 60s Scottish group, and a bunch of Child Ballads being posted, and I have seen individual requests answered.

Until the majority of us have high-speed access and storage gets MUCH easier, I suspect that the project of a BIG central location in not very feasible, and that tapping sources in places like this is a more likey way to find what you need. (I just learned that someone has a copy of an LP by Walter Forbes, a banjo player of the 60s, who did a version of "Poor Ellen Smith" that I have been looking for.   

I do agree that a central repository would be wonderful, but I see that everyone has already noted how difficult that might be.