Two words: Bead Seat. They work to keep air flowing all the way around/behind/under you. Add in one or two of those 12v turbo fans from your friendly local truck stop to keep air circulating around her feet, and/or directing air at her. ----- I have used a bead seat under me when I ride in the heat for many years. Prevents damp butt/crotch syndrome by allowing perspiration somewhere to go and keeps your underseat temps down considerably. They just work. btw - I personally recommend light/natural colored beads versus the black ones that some are selling. You can leave them sitting out in the sun and they won't scorch you when you climb on.
I have a 12 volt flat fan that is about 4 inches square by 1 inch deep. It is supposed to move 67 CFM, gonna use it on a ice chest system. still looking for the right sized ice chest. I have to have it ready to go next week, no problem with that though. cut a hole in the lid for the fan motor and a hole for the vent, add ice and plug in the fan.......ya got an ice air conditioner.....
I thought about the same thing, considered using one of the larger lunchbox coolers with the A shaped top that pivots to the side.
Seems the Entrosys has finally gotten off the ground http://www.bikeairusa.com/home.html http://www.bikeairusa.com/reviews---testimonials.html
I have no problems riding in hot weather.It's the kids on an almost enclosed sidecar. This wouldn't cut it.