I don't mean to contradict anyone's statements regarding muscle memory, but I'm not sure how much of an issue it really is. I got a Dingwall Afterburner with fanned frets last Tuesday, and played a 4 hour gig with it after playing it for maybe a half an hour. Not one bad note resulted from my unfamiliarity with a new scale (and a different scale on every string at that), and it was a pretty "notey" four sets of jazz/pop/rock à la Steely Dan. It was also my first gig with this band, after only one rehearsal, and I was still confident enough to throw caution to the wind and play it with a brand new, unfamiliar bass.
Again, this isn't meant to contradict anyone's opinions, just to say that I wouldn't worry about changing scale lengths being a big adjustment.
Oh, and to get back to the original post, if you're looking for a 4-banger with a bit more string length for detuning, you might want to consider a Dingwall, especially in the price range that you were talking about. It goes from a 34" on the G to 36.25" on the E.