An interesting academic tool
This kind of RSS feed might indeed be of interest to researchers and academics. Basically academics rate journal articles and post their thoughts onto this website. You can get an RSS feed of a particular contributor’s postings, or on your own search terms, for example. So it is a source of lots of RSS feeds.
It is a bit american biased again, but it does have potential.
I found out about this site through the Internet Resources Newsletter, so I suppose that is a source of RSS feeds. (http://www.hw.ac.uk/libwww/irn/irn151/irn151.html)
I suppose that RSS feeds are not something that you find by doing a search for RSS feeds, rather they are things that you pick up as you go along (& presumably delete as you go along, too). So that would be a reason why there isn’t a directory of them.
I’m still thinking in Web 1.0 mode, presumably!