The current winner is Abiword. Ok, so it silently converts Word docs to RTF, but I have tested sending a Word doc to the N800, editing it and sending it back and editing in Word on Mac OS X, and it seems none the worse for wear. Probably there are some sophisticated document styles or fancy structures that might not make the transition, but we don't use too many of those in my current situation... the text is very small, but it is usable - and the cursor keys actually work, unlike Google docs. And Abiword is faster than Google docs. Thanks everybody for your help, much appreciated!

/Neil