I have not had a chance to play with .net at all doing mostly java development. The RSS format looks very easy. It seems like it would be a useful plugin.
Well.  I have downloaded the comic plugin and started modifying it for rss news.  I am sure it is pretty buggy, but at least the basic logic is there.  I also need to clean it up changing the names of the variables from the comic stuff  to something more relevant.  I also have only tested it with 3 feed sites.  Techbargains, slashdot, and pc world. So far so good.
Any either big sites that I should test with.
Also I have not figured out how to get rid of the daily comics title at the top.
I have not had a detailed look at the Comic Plugin code but Its probably in the skin.xml file.
As for sites with RSS, there is freshmeat.net, sourceforge.net and I'm sure others will send on more. The RSS stuff is pretty straight forward. I did some stuff in php before to generate and parse RSS feeds. What versions are you going to support?
Change the getSkinSubdirectory() method to return "RSS", then copy the existing C:\Program Files\devnz\gbpvr\skin\Blue\comics directory to C:\Program Files\devnz\gbpvr\skin\Blue\RSS. Then edit the skin.xml as appropriate.