This thread started in 2006. It is now possible to go to YouTube, enter Marxophone in the search box and find a few performances on the instrument. In this video, Katherine Rhoda explains the instrument and then plays it.

http://www.youtube.com/watch?v=7A9iIQj2mO4

It seems to me that with it one would get the effect of a hammered dulcimer while having less to learn and less to carry about.