Back on October 17th, I ordered a set of "Black Edition Carbon Fiber Sport Legs" from eBay seller radioshackus (not to be confused with Radio Shack). Anyway, they arrived today from Hong Kong and I installed them tonight.
They came sans instructions but after looking at the pic on the eBay listing I figured it out. I'll note that if you get these legs or something similar, you will need a good, properly fitting Phillips head screwdriver to remove the OEM Yaesu screws holding on the carry strap brackets. They are in tight.
A couple of pics of the legs as now installed on my radio:
If you prefer to order FT-817 legs from a US vendor, see here. Note that while the seller is American, these are made in Germany.
Compared with an external stand, the folding legs are a lot more convenient and add no noticeable weight to the radio.