Admin, Since that is my stand ;D I feel qualified to answer.
That is for snowmobiles. You can purchase them about anywhere. That particular one was purchased at Haydays. I have a much heavier duty one that was purchased through a snowmobile vendor, but I ended up with it used as I am too cheap to pay what they sell that one for new!
They are designed for newer sleds so they are two wide for most of the vintage stuff, but I make doo by putting a board under the sled. The Mark's and Oly's are light enough they can lift on or off easily anyway.