Following up on my mobile thin client post, I decided to let off some steam, grab the Windows CE 5.0 Platform Builder evaluation, and take advantage of the years I spent doing Windows development to investigate just how feasible the concept is, software-wise.
As it turns out, the builder can generate a full Windows CE 5.0 image that can run on a standard PC (all it needs is a DOS boot disk and HIMEM.SYS), so half an hour after installing the software I had a bootable CD-ROM image complete with IE 6.0, a Remote Desktop client, Office and PDF viewers, the works - all working, all fitting in less than 32MB.
Sadly, the Platform Builder evaluation comes with a very limited set of drivers for the CEPC platform, so I had no working network support - and although there are NE2000 and Cisco Aironet 340/350 drivers, the network configuration UI wasn't all there, either.
But I had VESA graphics, and there was even a choice between an Explorer-like shell and a simplified "Windows Thin Client" shell, so I was tantalizingly close to what I envisioned - and without writing a line of custom code, or messing about with configuration files. An OEM would have zero trouble building a "mobile thin client" with Wi-Fi support, and most of the real work would entail setting defaults and building missing UI features.
One of these days (assuming I ever find the time) I'm going to grab myself something like a Toshiba R100, set up a Windows CE development environment and have a serious stab at this - either that or try to shrink XP to run off a flash drive.
It's a bit, er... ugly, but, again, trading built-in storage and the bloated hardware requirements required for running XP for a bigger screen and an ARM CPU (or even a low-end x86) would make it a whole lot more interesting.