In my experience I don't think the coloured update system will ever work.

A long time ago before WordPress had built in notification or upgrade support there was a similar type of worm going round and lots of people hadn't upgraded.

At the time, as a community member, it saddened me and I did something positive to try and help the situation - http://blog.ftwr.co.uk/archives/2005/06/27/wordpress-version-check/

I created a plugin to provide an update notification and that plugin had a colour coded update message and even pointed you to the codex page about alpha code being not supported if you were brave enough to be running trunk.

The things I learnt:

Colour coding and flashing beacons don't make people upgrade quicker - they just create noise and make you complacent when it isn't red and flashing.
People still ignore the update messages - There are people out there still running my plugin in WordPress 1.5.2 installs - now that is what I call ignoring upgrade messages