You probably are better off with a laptop or a tablet/convertible still because you can't guarantee a desk with a screen under those conditions, not to mention that the performance you can get from a phone today given it's power and thermal limitations is still quite limited.
If anything I would love to see a modern version of the Droid/Milestone I never understood why Motorola stopped making them, the Milestone was by far the best device I ever had.
Not to mention the security issues of relying on a Hotel/whatever's input/output devices.
Check out the Gemini PDA on indiegogo. Looks to be the successor of Psion or the droid 4.
That's really not in the same class as the Droid/Milestone.
This is an ultra small laptop, much larger than a phone and cannot really be used as one.
The Droid wasn't bigger than an average Android phone at the time and still packed an almost full keyboard and a dpad.
For such a setup to work and really make sense though it'd have to be available as near-ubiquitous infrastructure one could expect in every hotel and every office.
I suppose, however, the travelling tradesman / digital nomad target audience just isn't large and profitable enough (as of now at least) to warrant such a large-scale infrastructure undertaking.