Via vowe dot net : Collaborative RSS Newsreader for Notes and Domino comes news of Madicon RSS reader, a R6 product, not freeware, (it starts at 25 Euro per user) but you get a fully functional free trial for 30 days. Looks very slick passed on the OSX screen shot Vowe posted.
Also looks like another RSS/Blog reader, Studio Blog Reade, is due out next Monday, with lots of functionality (after having dealt with LotusXSL.jar and XML4J.jar files problems.