I used to have one of the original Jagmasters, but I sold it years ago. A couple of years ago I picked up a 70's Ibanez Jazzmaster copy as a project guitar, which is essentially a Jagmaster. Eventually I'll get around to fixing it up. I plan on throwing a couple of p90s into it.
Are you sure you have the short-scale Jagmaster though? From what I remember, only the originals were short and then more recent versions were normal scale length.