I was playing with the idea of creating my own RSS feed also with information that I find on others RSS feeds (with the proper links in place) Plus Information from my own store, i.e. specials, new products.
I am playing with RSS 2.0 for PHP
http://www.2rss.com/ for taking information from a database and writing an XML RSS Feed.
And I am playing with RSS2HTML from Feed For All at
http://www.feedforall.com/download.htm for displaying that feed I generated myself. Both are free scripts
I've successfully integrated it into XCart no problem I just didn't finalize how it would look, and put it to the side because of other projects. All you have to do is call the RSS2HTML script from your xcart template and make sure that you've set it up to look the way you want. There is probably an easier way. I want to look at BOOMER's code for displaying in X-Cart, but I'll still use RSS 2.0 of PHP to create my own Feed.
One thing that you guys should keep in mind is, that if you are including any links from the RSS feeds you should use a little JavaScript to supply the link so that Search Engines will ignore the external links. External links will just be giving away Page Rank.