well, I found these...
Handheld PC Professional 3.0 SDK
Handheld PC 2000 SDK - USA Version
Windows CE: Standard Software Development Kit (SDK)
The first one is for Windows CE 2.11 (or higher) and the second one, I think, is for Windows CE 3.0. I'm pretty sure that's the one you're looking for. As for the third link, I don't know if that would be any help at least for accessing the ROMs or DOCs, but it's for Windows CE 4.12 which is the .NET (Pocket PC 2003)
You can also download the source code now for Windows CE 2.11 and 3.0 from MSDN. If anyone wants it I can get a hold of that but that would require complete recompiling and rewriting of code and that could get messy and time-consuming. I personally would rather see what you're thinking of, Glitch. Borrowing the core from a similar MIPS architecture device.
Is there any way I can get a hold of any of these devices you keep referencing? I would love to toy around with it. For bragging rights only, I came across an Intel Web Tablet at a thrift store, new in its box. Came to find out it was never put into production and I was actually holding a developers version. There's only a couple hundred in existence and the only other one I know of is in a museum! It has no internal caching and uses a host PC for wireless internet and file storage and the GUI runs entirely off of an Apache web server of HTML files. Handy for rewriting and using for other things. :)
Anyway, that was just a side thing, but I would like to know how to get other tablet PC's of the CE variety. Ebay is not a great place for such rarities.