Just throwing this idea out there: Have you considered stringing your 4 B-E-A-D until you can afford a 5er that you'll fall in love with?
Won't he have to file the nut and maybe the bridge for this to work right making difficult to set it back to EADG later?
I agree with the general consensus here. TB Classified, CL, or Rondo are the three best sources. And I find that I often intermingle them as far as research goes. The TB classified are where I've found the truest prices and I don't hesitate to reference them when I am dealing on a CL bass.
Good luck with it, I did the same thing about 4 months ago and ended up with a great deal on my Fender Jazz V which has been my main player for 3 months now.
...I knew I couldn't go wrong with another Ibanez...I'll get some better pics today now that it's daylight...