Just a quick followup to this thread. Thanks to everyone who posted suggestions- I ended up with a Palm TX and it's almost exactly what I wanted. Not only that, but the device draws occasional semi-incredulous reactions of "can you still buy those things?!?" from tech-savvy smartphone-wielding colleagues.

The only niggling problem is that because the TX is an antique by current standards, it doesn't handle WPA2 so synching has to be done via cable. There is a patch for this, but it doesn't work on Chinese Palms, so I will probably return it for a US one.