On the other hand, in 2004 I saw Jefferson Gonçalves play one tune with the 12 diatonic harps.Michael Rubin sez : excerpt ,
" Hey,
In 2006 I did a performance at SPAH where I used a Special 20 in Bb to play in all 12 keys.
http://www.myspace.com/rubinmichael
Hope you enjoy it! Michael Rubin "
Fernando Toral Argentina