Actually getting a yellow one would be pretty easy if you had a friend in the industry. For the other colors.. the magic number is 5, not 3.

 

That black piece is just the normal plastic cab corner that is on all of the new cabs. Ford just won't paint any of trim pieces yellow to match like they do on the rest of the colors. It's kinda cheap of them if you ask me.
The color is school bus yellow and it's a special paint code that Ford will only put on the XL and XLT's with grey cloth interior. Ford also limits the options that they will put on the truck. You don't have to order multiple trucks to get this color. They have ordered one at a time but you will usually have to wait quite a while to get the truck, I suppose until Ford gets enough orders to paint that color.
Some of the options are (im going from memory)
#11500 GVWR
6.2
4.30 axel ratio
176 wheelbase
Camper package
Upfitter switches
Extra heavy duty alt
Sync 3
Roof clearance lights
XLT value package
Dual batteries
Luckily the fuel doors are painted yellow on these trucks.

 

That's plastic? I thought when I looked at one the cab corners seemed kind of plastic sounding when you tap it, but then again the rest of the truck sounds the same way.

 

Hold on, I need to go get my sunglasses before I comment.