I coach an elderly cyclist who concentrates on Time Trials.  She has a very difficult time staying cool.  She doesn't sweat much if at all, so no real evaporative cooling.  In combination with her general discomfort in heat, it's not a good combination.  Every year we work on heat acclimatization, but it makes a very small difference for her.  So, I am starting to look into commercial or homegrown cooling systems.  I know Garmin had worked with these a few years ago, but I don't know if anything ever went to production.  Basically, I am thinking about something like a slim Camelback under the jersey with a frozen bladder.  Ideally, I'd have a bladder-only system with straps that covered a majority of her back but was very thin (and frozen).  Thought I'd start here to see if anyone knows of anything currently in production.  Thanks in advance...