Mark,

No, a prone recumbent is not a contradiction in terms. Recumbent
means lying down. Prone refers to lying on your stomach, supine
refers to lying on your back.

Prone recumbents were first patented in the 1800's. Many have been
built in the last 125 years. A few good examples are shown at:

http://www.geocities.com/rcgilmore3/prone.htm

I actually rode a homebuilt, made from a BMX bike about ten years ago.
A local bike dreamer, like myself had put it together. It was great
fun. I felt like Superman!

Back in the 1980's a prone streamliner was raced quite successfully in
HPV races.

Warren