Bernard,
I have a friend in St.Louis that has two of the Rose machines you have
described. He has made some very interesting modifications to them that
allow him to actually carve the rosettes in wood. He motrorized the
cutting head. Just incredible. He makes his own "program" plates out of
plexiglass. If you live near STL I'd be glad to put you in touch with
him. BTW, the bowling ball is a great idea. Also, I see large stainless
or chrome spheres at the junk yard all the time. They come out of large
ball valves. Good luck!
-Mike