How about a Datafeed Optimizing Tool?
Affiliate marketers who use datafeeds for promoting affiliate products have a pretty good idea about the technical difficulties that you encounter on a day to day basis. Issues like duplicate content, remotely hosted images, etc are tough to deal with in the beginning, but if you spend some time and effort, you can get around it. Problem starts, when you have to update your datafeeds on a day to day basis.
I have a few tools that help me get around these (some of which are available for interested marketers on my site) while some are pretty custom built for my requirements. Datafeed Optimizer is a new product in the making that takes working with datafeds to a whole new level.
It should be ready for testing in a couple of weeks. I will post more details about it as I get to put it to test.
June 30 Update: The tool is ready and being tested right now ... it looks super awesome and has a built in Datafeed Editor which allows you to work on the feed before you can import it into your MySQL DB. With the last test, I was able to work on a 156MB CSV file, get unique values, set some find and replace rules (which can be re-run on saved feeds over and over again) and export it back. Importing Over 108,400 rows took 20 seconds, working was super quick, and exporting the file back took another 10 seconds. Very satisfying results.