I’ve managed to get my hands on the Dial 520 handset, and am happy to say that it is now my preferred device for softphone calling when in my “mobile office” (i.e. anywhere I’m working for >1 hour). It’s a USB device is small and simple to use, and doesn’t require drivers (tested on Windows 7 and Vista).
It automatically integrates with Office Communicator (e.g. dial buttons, answer/hang-up buttons, LCD display) and gives really good quality audio for such a simple device.
So with the GN9350 in my home-office, the BT530 on-the-road, and now the Dial 520 when semi-mobile, I’ve got a pretty good road-warrior setup for UC and collaboration. (I’m not paid or sponsored by Jabra, I just like their hardware and it fully integrates with OC)