Oh yeah we do!I'm almost certain harmonica players don't get bad cases of g.a.s. like us...
I started out with a simple Hohner Marine Band model when I was 10 and loved it. Then the teen years kicked in and I learned of all the other keys they're offered in (at the same time hearing John Popper do his magic) and the game was up.
Every music store I visited offered some variation of the standard classic: Double harps, multiple keys on the same harp, etc.
And of course all were willing to "offer me a deal" to buy them.
I still carry the old Marine Band in a Buck knife case just to keep up the music, but harp G.A.S. is for real!! =-D