Get it on the ConnectIQ store -- https://apps.garmin.com/en-US/apps/58119f8c-ff77-4cdf-a0bf-35234323dd9a
A simple fork of the very excellent GRun data field, that simply adds coloring to the cadence field https://apps.garmin.com/en-US/apps/bf56e088-aefe-4fb4-8f16-b2e136b996a9
See here -- gcormier9#4