The French organist Jean Guillou had an instrument made for himself a while back which might be of interest to some here. It is a pedal piano. It has the standard piano keyboard, but underneath the piano is an organ pedalboard. It is a rather strange looking instrument as there is a smaller piano right underneath the main large one. You may see it here.

http://jeanguillou.artistes.universalmusic.fr/Borgato/borgato.html

I would love to have something like this, actually.