Seon, you seem like a resourceful guy. What about going for a power window unit at that location? You have plenty of room in the body spaces and these rod companies make all kinds of power window kits. Best of both worlds. Tie them all together at the driver console like a new vehicle-6 switches with rear lockouts. R&B's automotive is chopping thier showcase burb. Call them and see if they're going to do power side windows.
Check that.... they used a panel and cut out the panel. Oh well, you can still be an innnovator
http://www.rbsobsolete.com/