The Toto Guinevere works well. I've sold over 150 of the Soiree / Guinevere toilets so far, many of them repeat sales.
They have a 3" flush valve and 2-1/8" trapway.
You still hear the water leaving the bowl on a toilet unless you go with the old 9.5 gallon toilets that moved as slow as a glacier.
I sell a bunch of these in the Los Angeles area too.