I am going to a risque halloween party this year as well and I am looking for ideas. One that I thought about doing was going as the Naked Chef - wearing only a Chef's hat, and apron. But then I looked at the pictures the host posted on his blog from several halloween parties in the past and saw that that had already been done. That would be a very comfortable costume and would allow lots of skin to show.
Another idea is to go as Pan - get some chaps and glue on furry hair on the legs. you could wear a jock with furry hair glued on that as well. The skin showing would be a bare ass and bare chest.
I am thinking about going as a UPS delivery man - tight brown short short pants, tight brown shirt with sleeves cut short and a box wrapped in brown paper with hole cut in the back of the box to stick my package through with a removable lid attached at my crotch. Not sure if I will stick my dick through a hole in the box or not. "I have a package to deliver to you". LOL
Good luck and have fun at your party.
You will have to post pictures here with you in your costume