I'd like to share with you what I did for my rear window, and many of you folks may have already done something similar. I too was tired of having to have a key to always open the rear window.  So, I schemed up a way to power the window at all times from the dash switch without having to splice a single factory wire.
    I have a dual battery system, and a 1-in/6-out auxilary fuse block behind the glove box, (I cut away a small portion of the back wall of the glove box to accomodate this). The auxilary fuse block, of course, runs off the auxilary battery, at least when the truck is off. So, I first took a fuse, (any old fuse) and blew it.  I then put the blown fuse in the factory fuse block in the position for the rear window fuse. Now, the window is obviously not getting power from my main battery with a blown fuse.
    I then took one of those little power taps (these are little clips which are specifically made to clip around an ATO style fuse) and put it on the "dead" side of my blown fuse (i.e. the side which is not supplied from the ignition switch from the main battery). I then connected one end of a 12 guage wire to the fuse power tap with a female crimp on connector, and ran it across the dash over to my auxilary fuse block. I moved the original mini circuit breaker over to my auxilary fuse block to retain stock amperage protection.
    Whala! My rear window now works independent of the ignition switch, it draws from the auxilary battery when the car is off, and as an added bonus, my door windows are obviously on the same circuit as they now work all the time too.
    I have been using this setup for several months, on cold days when the window doesn't want to move and hot days, with no problems. I didn't have to splice a single wire, so should I need to return to stock, it would take under 3 minutes to reverse the above steps.
    Some of you have probably done something far more sophisticated than this, but I thought I was pretty clever for thinking this up, and that's not a feeling I have often.