I've had the opportunity to be on several middle east royal flight department aircraft and to say they are lavish is a complete understatement. Gold fixtures everywhere...door handles, toilet handles, trim around instruments, power levers, etc. I was in a B707 (shows my age) and in the shower was another door with what looked like a glass truck spring. It was hollow with what looked to be gold dust at the bottom. I asked the crew and he pushed a button, and the gold dust (a good guess on my part) began swirling up the spring. I couldn't imagine why you would want to look at this while showering. Actually, there was a purpose. You wrap your towel around the spring and it heats the towel to 100° so the user isn't chilled by a cold towel.
Anyway, I could go on but you get the point. I've been on royal 707s, A310s, 747/747SP, Bach 111s, etc. All exquisitely outfitted, yes, for a King!
And now, back to the real world.
2000Flyer
PS - I guess I should be more specific. When I say "ON", it was just a tour. I was a line manager at a mom and pop FBO at the time.