I'd go wired or GPS-based -- one less battery to worry about, plus less interference.
A backlight would be great, but it would need to use the same black-on-white as usual. I used to use a Blackburn Neuro on my road bike that was useless in twilight because the black-on-white display changed to white-on-black (well, green-on-black) when I turned on the backlight (that, and it became illegible whenever I was too far off-axis).