Some of the sites that have RSS feeds are available on LiveJournal. You could always create a LiveJournal page and subscribe to the feeds. Then they show up on your friends page. Here's the ones that I know of...
(note, that the last one has a typo... nudge, nudge, wink, wink)
If anyone knows of any other MAME devs with RSS enabled sites let me know.
Someone could probably create a page here on MAMEWorld that aggregates all the RSS feeds into a single page with the newest content on top. Maybe break it up by month or year to keep the page length manageable.