It must be time to move on from the cassette toilet, which have been around for a long time. I wouldn't miss the emptying!
The Cinderella toilet options are gas or diesel for the burner with some 12v power for the controls.
Cinderella Travel: Sustainable, water-free incineration toilet for RVs & caravans. No cassettes or tanks. Made in Norway.
cinderellaeco.com
Not straight forward to retrofit. It will be interesting to see how many builders offer it as an option like Auto Sleeper are doing.