I have thought about this as well.
Desanits makes a seat holster - up front, between your legs.
Glock 19, 23, 32 Holsters : Glock 23 Holsters : 19 Holsters : DeSantisHolster.com
I am looking at the Protech seat buddy holster - $21
(If this link is not appropriate, remove and let me know please)
Pro - Tech Seat Buddy Holster, Holsters, Pro-Tech at Sportsman's Guide