You seem to be very focused on having your Transfer Case do something in Neutral.
I'm not saying that you don't have a problem with your 4WD system, but I am not so quick to rule out user error, especially since you have not owned your 4Runner for that long and have never made use of the 4WD system.
Your Transfer Case (4WD lever) should always be in 4HI for day to day driving (even in 2WD). You simply switch between 4WD (multi-Mode) and 2WD with the button on the T-Case Lever. You can do this on the fly at speeds up to 50MPH if I'm not mistaken.
If your t-case is in Neutral, your truck won't and can't move under its own power, no matter what gear is selected on the transmission. Your 4WD light will (and should) blink in the dash.
Do you have a Center Diff Lock button as well?
Here's a good reference about 4runner t-cases and all the different 4x4 modes: http://www.toyota-4runner.org/3rd-g...-transfer-case-awd-multi-mode.html#post669885
I do have the center diff lock button as well. Replaced the rear end a few weeks back (the stump), but sadly couldn't find and e-locker.