Ipe or Teak is the answer for your application?
You can contact ipedepot.com for 5/4 grooved ipe tropical hardwood that you can install with edge clips and no nails or screws in the top. You can have them mill the first board or 2 7/8 or an inch if you can't squeeze the 5/4. They offer awesome service. I can send you photos of my ipe decks. that I built with all Stainless screws etc. If price is no object Diamond Tropical hardwoods can get you 3/4" Teak. Both of these woods are super strong so you can go the thinner weight. I would do 12" on center joists.
Re: very thin deck material?
On many houses I have worked on recently, the deck has been finished with 5/8" T&G plywood and covered with an outdoor vinyl flooring. I believe this would fit, though it might be close. I don't have any personal experience using this, but I have seen it on $1 Million + value homes and on economy duplexes, so I assume it has some good things going for it.