I'd to add colors to custom fields so that it gives more visibility to certain items. For instance, we use the status for workflow but we've added a custom field for the true status. For instance, we can have a feature that is in progress, but has no developers allocated to it we mark it "At risk" but we can't color that red. There are other instances when the feature hasn't been started but planning on it shows it is blocked by another feature so we have it marked "blocked." It's just difficult to see within all the other fields if it isn't colored.