Well the wheel didn't come loose during his 50mi. race yesterday, so that's good. =) I think I'll have him bring it over this evening after work to tear it down and take a closer look at it. If I can't get that washer moved to where it should be, we'll be off to the shop to ask them for a replacement axle. The shimano components are well within their warranty, so if there aren't enough threads to get proper torque, we'll ask for the shop to supply the part, either a couple of mm longer or simply threaded to the ends.
I'll post up what I find. Thanks so much to those who shared your experience with this hub. It really helps to have first hand accounts from experience mechanics.
-Jeremy