Good luck if you can convience his to settle for a 15.4'' wide screen than I could recommend the Dell Precision Mobile Workstation M70. We have one user doing heavy ESRI ARC GIS applications on one. I also fear it might get above his price cap by the time he were to get an ideal CAD configuration. I would really suggest he consider an option like this with a dock so he can ustilize a standard keyboard and destop disply at his primary location then still have great CAD performance on the road.
A fellow I do some volunteer work with has asked me if I know if such exists. He wants a large screen..17'' at least. He does customer metal work in stainless and aluminum and does these uses CAD on the shop PC for design work but wants to be more portable. He does not want a 15'' screen at all. I suggested a business class laptop w/docking station but that isn't going to help. About all I can find that might fit is the Apple G4 Powerbook but his PCs are all Windows based at this time. I don't know CAD software or whether any is available for this Apple. Is there anything in a Windows PC I can suggest or is the Apple about the only thing out there? He says he's willing to spend up to $3500. TIA