I have no doubt he can design a bodyshell. Except that a shell is pointless without a planned mechanism for it. Both have to be designed simultaneously, or the shell has to be designed for a specific mechanism. Otherwise there is no way to plan for attaching the shell securely to the mechanism.
I have an EP5 of my own ready to go. But I'd rather concentrate on the EP3, EP4 and EF4 before the EP5. I'm in the process of testing with the ProJet XHD resin, which is double the resolution of the Shapeways FUD. If that is successful, then I'll be building some New Haven electrics before the year is out.