Thanks for the responses all. What I've learned so far is:
1) there is some interest in general in the concept
2) usefulness/popularity of the Character Archive (or whatever it is called) will likely depend on several factors:
- amount of characters
- appropriate 'tagging' and descriptions so what you want is easy to find, and the site isn't just a jumbled mess
- quality/usefulness of the characters themselves
- availability of a variety of formats
3) with the appropriate disclaimers, the site is perfectly legal
I make sites for a living, so the technicalities worry me less than appropriate editorial efforts to make the site a living, useful thing rather than just a character graveyard that gets 10 hits a day.