My point about airfield systems downgraded was, what if the ILS was off line, and you had to fly a VOR? I have autolanded off of Cat I approaches many times too. I was't aware that it was a "secret".
I admit your systems knowledge for a non engineer/pilot is impressive. However I still stand by what I say. I have had my lot on this, fed up with it, and can't be bothered to waist my time posting on this any more.
I believe the GPWS warning would be "Too low gear." ie Flaps in the landing config and no gear. From your post "Flaps at 20-30nm gear at 10nm" There would be an immense ammount of noise, easy to lose concentration.
One other thing springs to mind, they wouldn't let you anywhere near the flight deck in this post September 11th environment.
The flight deck door would be locked, and bolted! As for the Flap, gear thing, consult the QRH, it will be found to the right/left side of you depending whic seat you are in. That will give you some good info.
Happy landings! (And may they all be simulated unless you have a licence.)
Eff Oh.