Ya heard me!!! I can't find any documentation supporting my claim though. Aside from a pic of him rocking out on a telecaster which shows he does play guitar. Apparantley, it was the NEC in Birmingham if memory serves me right. He came on stage and treated the audience who were expecting all that smooth stuff he does to a bit of heavy rock, which saw him brandishing an EVH. I could be way of base here though. I was only told this. Never actually saw it myself.
Personally, I havent found anything about the signature gtrs that do anything for me. I love my Axis Sport in its sound, playability and finish. Still if not for that gtr, Id still prefer to play something not attributed to a specific player. Id most likely play a Axis Super Sport or a Silhouette.
Whether my guitar is a "signature" or not means absolutely nothing to me. What does matter, is how the instrument plays and how it sounds!
I actually got into Dream Theater because my guitar teacher had an Ibanez JPM100 P1 (the original Picasso thingy), and I thought it played and sounded incredible... Hence, I actually went to check out the (to me) unknown guitar player with the amazing guitar! Well, I dug the music, was floored by mr. Petrucci and ended up buying my first siggy guitar to boot - a JPM P3 (the black/white Picasso-thing). Since then I've owned three Fender signature guitars (a Ritchie Blackmore and two Yngwie Malmsteens) and a Musicman John Petrucci.
All of these guitars were bought because of specs, not signatures: I got the Fenders for their scalloped fretboards (can't really get that anywhere else) and sold the Ibby JPM to get the Musicman, because I was getting tired of Floyds, but still wanted that tone and feel (I was initially disappointed with the EBMM neck shape for that very reason... I grew to love it though ).
I believe I'll jump on the siggy train yet again, when my raport with my bank allows for a new 7-string... Guess which one
Cheers
Eske
P.s.: I'd never get e.g. JP inlays or a scratch plate with SRV carved into it - it's simply to player specific IMHO... oh and I also don't like how these things look.
Every guitar has someone's "signature" on it one way or another. Just play what you like regardless of anything other than how you think it sounds/feels/plays.