I've actually been pondering why most folks haven't simply replaced anonymous FTP with HTTP. The transmission advantages of days yore simply don't matter with broadband. I know there are exceptions where folks need certain features, but for the bulk of exposed anon-ftp servers out there, FTP just isn't necessary.
Just my $0.02.
That's pretty much exactly what we've done... for anonymous and authenticated -downloads-. (It's nice that http clients universally support SSL, unlike ftp clients).
What we still need anonymous ftp for is to provide a location for -uploads- from clients and partners. I guess we could potentially set up something with funky permissions and http PUT commands, but ftp servers already have a well-documented configuration for 'blind' anonymous dropboxes.