I know about kindlefeeder, but my thought was combining a prioritized Instapaper with a prioritized Kindlefeeder, to give you a daily digest of articles you'd like to read. Backlog and lower priority feeds would fill the digests when you dont have new, high priority articles to read. If you used Instapaper + Kindlefeeder, you'd have 2 digests to read.
Combine that with a hack in the social features of the Kindle to kind of mark "I liked it" or "Not so good" and you can get a machine learning algorithm to automatically select the articles to put up in the list. Sweet :)
Create then iterate ;) Thats further down the road.