Maybe it was those. But they looked home spun. Literally just a pair of vans with a little cavity carved out of the sole and some clips installed. The post is gone so I can't find the pics.

It seems like vans and other shoes are thick soled enough to make it work. Use a dremel and an exacto to make a little inset, Then you would just remove the shoe bed and rivet or bolt them on. You could use silicone or shoe goo to seal it up from water, etc.