You asked and this is it: l'Angolo di San Pietro. They've only been open for a year and are a tiny bit expensive, but this is it if you want the best.
The top photo is the view from the roof terrace and the bottom is from one of the bedrooms. It's a historic old little palace. Really a tiny place, with a few nice sized rooms. All renovated and new and clean. Rooms each have a small kitchen. The best location, the best views and the best place to boast about.
And you can host small private parties on the roof, too.
See their site and enjoy this fabulous place on your next trip to Rome: http://www.langolodisanpietro.com/.