I located some horizontal mighty mounts(for bike accesories not ski) at a local sporting goods store. They have 2 sets left at $5.99 each. As soon as I said "wing-rider" to the sales rep he wanted to unload them on me.

If anyone is having a hard time finding these, let me know. I don't know how much they are going for on isuzuparts.net or st. charles isuzu. 6 bucks sounded like a good deal.