Buddy seat on a D series?

Went to a small esate auction today consisting of all household items. The only thing farm related was a few very old brochures on farm tractors. There were 5 or 6 small boxes each containing just 5-10 brochures. Each box had a different brand with 1 box containing AC stuff. It included CA,D-14,D series and 1 on implements. On the back cover of the D series brochure it showed in a very small picture what appeared to be a D-17 with a passenger seat mounted on the left fender with a man sitting in it. It looked to be a full size seat-kinda like on a 190-with the wrap around armrests. Did AC offer such an option? By the way,I did not buy the brochures. I probally should have,they went for $17.50. The box with JD stuff went for $65.00 

It was a "Demonstrator" seat.  Dealer installed when he took the tractor out to the farm to demonstrate it and try to make a sale

I rember seeing one on a neighbor's D-14, when I was a kid.

Here's an idea I saw for a buddy seat on a D17 that was on the same ride I was. What he did was unbolt the fenders, got some long bolts and pieces of iron pipe and remounted the fenders. He had to run the rear wheels out most of the way, but he had plenty of room for a double wide seat. Everything was bolt on so he could remove it and go back to original. It took me a minute to figure out what he did at first, but was pretty slick. Wouldn't be practical for me since I have a rail type trailer and the 17 barely fits with the wheels all the way in.

I rode for hours sitting on the battery box of dads WF while he was operating the roto baler.