For the amount of money he's spending on auctioned domains, wouldn't it make more sense to find a 'related' (eg. backyardziplines.com vs ziplines.com) name and do exactly the same thing (set up a site, contact a partner, etc) and spend the thousands of dollars on advertising?

Maybe it's just me, but google doesn't really put that much stock in the url itself, does it? A non-scammy site and some good lead ins will put you high in the search results regardless, no?