Here's something that may generate some creative ideas. A year or two ago I bought a chilipad. Check out
www.chilitechnology.com for info. A peltier unit is in a cube (about 10" cube) that generates cooled or heated water which is circulated through tiny silicone tubes built into in a mattress pad. The tubes are barely detectible even without only a sheet on top.
It does feel slightly wet sometimes but it is so slight, I feel a fan blowing through the seat would take care of it. No mold or mildew even in the humid south where I live.
It definitely works in the summer. As I have two dachshunds who stick to me like velcro, I don't need it in the winter.
I think a combination of chilled water circulated through a pad PLUS a bit of air moving across the tubes will cool the driver plus handle any condensate.