Ford did that on T-birds for a few years. Mercury Capris (the early German ones) had them too. Consumer Reports used to bitch incessantly about such things. They finally gave up complaining about SAAB’s ignition key location. I find such things amusing, and would quickly adapt to them if it was in my car.
Not a bad idea. The horn button in my Prius is easy to find but a pain to use. This would make it easier, not that people probably want to encourage honking.
I knew a guy who gave up his horn for Lent.
I need to pull my left foot up, toward me. Otherwise my lower leg blocks the speaker in the door.
I had a '74 with the horn on the stalk along with the dimmer.
The spot on the floor where all my previous cars had the dimmer was a switch to pulse the wiper/wash the windshield.
Yes, I did unexpectedly wash my windshield at night a few times.
I always had one of these on my dimmer switch.
I miss the floor switch.
When I was a child, for awhile there I thought my father was switching to high-beams and back by a form of magic (he wasn’t touching anything!).
When I was first driving I got confused and when trying to flash the hgih beams to signal someone to go, and sprayed my windshield washer fluid instead. 
I never knew the switch was ever on the floor, and I never heard the term dimmer switch. Of course I only learned to drive in 1998.
I was always amazed when Pop would know just before the light turned green, and hit the clutch or whatever to go.
I’ve never heard it called anything else other than the dimmer switch.
'robable spam 'ported
When I was a teenager I drove vans with the floor switch. They were often to be found rolling around the passenger footwell because a driver wearing boots could easily kick them free of their mounting. Not unknown either, to put a foot on one and have it vanish through a rusty hole in the floor.
My current car does it all automatically; dim, bright as required by a sensor at the front. There is a stalk to flash or do it manually if needed as well though.
British cars used the term “dip switch”. The Triumph parts catalog calls it the “Headlamp dipping switch”. which is more accurate then dimming anyway.
Dennis
Moderator Note
This thread was revived by a spammer who has since been wished away to the cornfield.
Lucas called it the “off” switch.
I thought it was the 3 position Lucas switch - Dim, Flicker, and Off.
I think the headlight current went through the switch, making it Dim, Flicker, Smoke and Off
Dennis
I think it was on the floor in my '58 Volvo. I think maybe the first car I had with a column dimmer was a '66 Rover.
I always hated the floor button in Canada, where sometimes it would be frozen solid in a block of ice. The floor boards never thawed, and you’d be tracking snow on your boots up onto the dimmer switch area, and it would freeze up.
My '48 Chev had the step-on starter switch right next to the dimmer switch on the floor.
I drive a Toyota Echo. It has a dimmer switch, and it’s a separate thing from my high beams switch.
http://thumbs3.ebaystatic.com/d/l225/m/mOnChhQDPrLEPJG3oDPHj6Q.jpg
It dims the interior lights. I’ve never heard the high beam called a “dimmer switch”; it doesn’t function like a dimmer (allowing you to fine tune brightness) and it makes your lights brighter than usual so that would be a ridiculous name for it.
Did you read the thread? The switch got its name in the Olden Dayes when running high beams was normal and you turned your headlights down on the rare occasion you encountered another car.
Sheesh, kids these days. I never !! 
So it’s a term that old people use, no wonder I haven’t heard it before (I’m 40 by the way).
But presents a new problem, my feet keep getting caught in the steering wheel.
My vote for the wider utilization of domestics to headlight relays. That’s why the switch was on the floor to begin with, I expect, in pre-relay harness. The headlight wiring takes a long, circuitous (heh) path from the battery to the dash, down to the floor, back out to the front of the car.