If you can't try one first, it might make the most sense to buy one used. Keep an eye on the for sale forum here, or post in the wanted section. New Alembics lose their monetary value very quickly, but used Alembics seem to keep it. So if you get a used one and find that you can't get along with it, you can probably turn it around for about what you paid for it.
Oh, I keep meaning to ask - do you like the Mustang? I had a reissue and thought it was a great bass. Too bad Alembic doesn't make a Mustang Activator! (Those are the replacement pickups - put a set in my Telecaster Bass and really liked the results)
Good luck!!!