I drive a regular cab truck with a bench seat. I have a cabelas (camo of course) seat cover on it that has lacing on the sides to secure it. I've found that a right hand IWB holster can be slipped behind a strand of the lacing and hung from the clip. This puts the gun in very similar position to carrying it in a shoulder holster. I just have to reach across with my right hand and draw it, and it is between the seat and the side wall of of the cab/back edge of the doorframe where it is pretty much hidden from view to anyone passing by.
I don't leave it there when I'm not in the truck, but for longer trips its nice to put the gun there while I'm on the road and then move it to my carry holster when I get to my destination.
Fix it right the first time...
Use Baling Wire !