Here is the URL for my testfeed for RSS with enclosures:
At the moment it redirects (points) to the Feedburner feed of my regular weblog feed. This means that I can add enclosures to it.
Warning! This feed may change at any time and strange things may happen to it!
It is a test feed!
UPDATE: Didn't work with NetNewsWire and probably other RSS readers. I had to change the forward a bit and add index.xml.