It's shocking, I know, but I think someone is about to bring out a phone / PDA mix that will satisfy me. I say 'I think' because it's been announced and there are pretty pictures and a shiny spec but nobody's actually got their hands on one yet to see what it really does. Still...
It's the HTC Touch Pro.
http://www.htc.com/www/product.aspx?id=49518 News seems to be that it'll be out around September. It runs windows mobile with HTC fancy flow software on top. It has HSDPA, GPS, a slide-out keyboard, touchscreen, speaker, radio, wifi, bluetooth, and with WM6.1 should have Word (which I need for my reading / editing on the go). It claims to have a decent battery life, too, which will be one of those things that I'll wait for tests on. In terms of size, it'll be a bit longer and not quite as wide as my current palm. I have a lot of things to tick off on my list, and one of those things is quad-band (which this isn't) - I'd need to hang on to my current phone in case I ever go to the US, but since that's increasingly rare that's not a deal-breaker for me.
So... a few months to wait and see.