FeedBlendr lets you
Have a look at xFruits which can combine and mix several multiple RSS feeds into one. You can either enter feeds manually or import feed subscriptions form your FeedReader (as OPML file).
Extra Features:
- Combine as many feeds as you want.
- Supported feed formats: RSS1, Atom and RDF feeds.
- Supports Feed enclosures: Combine your favorite podcast subscriptions into oneamongst others.
