I had a google around when you posted this thread but couldn't find anything, I wonder if the 'EV' is some manufacturer abbreviation or, more likely, a one-off custom with 'EV' representing the obvious (Eddie Vedder). Who knows, maybe he hacked something together himself?
I thought I knew exactly what you meant, the Tululele, but I looked at my copy of the album and I see that he lists that too, so I'm just as stuck and curious as you are