Oddly, I notice an intermittent failure of my cruise control as well. It always seems to happen when it's obnoxiously cold outside. The problem is rare and intermittent. I can only guess that a vacuum actuator may be freezing temporarily. The problem goes away either in an hour or a day and doesn't seem to occur in summer months.

Make sense to anyone?

Does this sound like your problem or is your cruise control simply non-functioning regardless of any other factors?