By custom I mean out of the ordinary instrument -- it being significantly different than other standard instruments. Some examples: Uli Jon Roth's custom 'Sky Guitar' which was seven strings and additional frets (if I'm not incorrect on that one ..) Mark Sandman's two string bass guitar played with a slide -- (with apologies to Disneyland After Dark) Who are some other musicians that played instruments that were custom built and outside the regular specifications of most instruments? I can't think of many others, but there has to some out there. Slim Jim Phantom and his stand up kit? Tony Levin and his Chapman Stick? (I guess any dude that plays Chapman Stick could qualify, though, so maybe not...) First person that mentions Ravi Shankar gets a swift kick in the nuts and is kindly escorted out of the thread Didn't some play a 'keytar' or something? .. You get the idea.