I finally got around to getting this modification done. I got the dump bed working and the first question my son asks is 'how does it work?', I say you use your hand to dump it, he says 'why don't we hook it up to this button?'. So, if anyone has any ideas on a motor that would work well to dump it, let me know.
I've posted a full overview of this modification here. http://goetzeverything.blogspot.com/search/label/Arctic%20Cat