What a wealth of expressions you’ve found. I can only come up with a rather cruel one referring to someone in the world of entertainment who’s not very goodlooking. They are described as having a radio face.
I wouldn’t consider things such as “Hair Distribution Technician” to be true euphemisms, but rather simply humor.
There must be thousands of euphemisms in both British English and American English. Even Shakepeare used them:
“shuffled off this mortal coil” = die
Monty Python’s Dead Parrot sketch provides an extensive list of euphemisms for “die” (including Shakepeare’s):
“E’s passed on! This parrot is no more! He has ceased to be! 'E’s expired and gone to meet 'is maker! 'E’s a stiff! Bereft of life, 'e rests in peace! If you hadn’t nailed 'im to the perch 'e’d be pushing up the daisies! 'Is metabolic processes are now 'istory! 'E’s off the twig! 'E’s kicked the bucket, 'e’s shuffled off ‘is mortal coil, run down the curtain and joined the bleedin’ choir invisibile!! THIS IS AN EX-PARROT!!”
I’ve also heard a rumor that the Brits often “spend a penny”. I personally would be more likely to powder my nose.
Two other ways to tell someone his fly is open (probably the most common where I come from) are, “Your barn door’s open,” and, “Having company?”
When someone is scratching his derriere, we often point it out to him by saying, “Going to the movies?” Generally, he will stop scratching then, but if he doesn’t get the message and says, “No, why?” we tell him, “Because you’re already picking your seat.”
“I have to wash my hair that night,” means, “I won’t go on a date with you, you have no chance with me, and never call me again!”
When I was a very small child, if my father said, “See if you can pull a Cadillac out of there for me,” I knew he wanted me to stop picking my nose. This was just his own eccentric saying.