@farmerman,
Since you keep a laptop in the truck or luggage your best bet is a nettop. I've looked at all the PDA's, smart phones, multi-function hand-helds, iPads, blah...blah...blah.
All of them are weak compared to a nettop, thus I do not own any of them small devices. I do own some single function mini-devices however such as a high resolution four channel audio recorder and a HD video camera etc.
Nothing comes close to a nettop overall, they have the power, versatility, screen size and keyboard needed to do many jobs really well without being too big. Just get a cell phone with the features you need as an adjunct and you're off to the races.