Question: RSS reader optimized for Craigslist and Kijiji

Wanted, an RSS reader optimized for Craigslist and Kijiji. Willing to program myself, if necessary.

I'm looking to optimize my use of RSS feeds when perusing online classified adds. I've been using Thunderbird, and I've set a few message filters to save me some time, but it isn't enough. Some of the features I need:

1. Sophisticated kill scripts, to avoid spam, duplicate listings, and items I'm simply not interested in
2. Permanent storage of the listing and pictures for market research purposes. This would include monitoring changes, and recording the date of listing removal.

I'm sure there are a million features I haven't thought of, but those two are really key, and they are not at all typical for RSS readers, as far as I can tell.

I'm a junior programmer, but I'm happy to take this on as a project. Hopefully, as a plugin for existing software, or a modification of an existing open source RSS reader. Happier still if somebody has already made it, of course!

And as an adjunct question, I'm very interested in recommendations for ebay software. Again, looking for permanent caching and tracking of auctions. I've heard of some ebay market analysis services, but paying a subscription isn't really an option, unless it is very cheap.