Turning this idea into something that could be done at home wouldn't be too difficult, all you'd need to do is come up a few cans of sterno (or even just one if your party is small) and the accompanying S'mores accoutrement to go with it. It could be done on a patio, or small balcony without any issues and if you're daring — used inside.
Yes, there would be some char and smoke that goes with it, but as long as you request that guests don't fully char their marshmallow, you should be just fine without smoke alarm worry. As an added bonus, your home will have a wonderful campfire smell without having to purchase any scented candles!
Is this an idea you love for small spaces or would you rather be S'more-less and just wait until you have a real open flame?
More S'mores Inspiration at The Kitchn
• Nutella and Banana: Dressed Up S'Mores
• Marshmallows on a Stick, But Better: S'Mores Pops
• Found: Mega Marshmallows For Your Summer S'mores
• Look! Individual S'Mores Bags