Several companies have been working on diesel and multi-fuel versions of the rotary but as far as I know, none have made it to the consumer level yet. In each case though, the engines are significantly different from the typical Mazda type that common parts are unlikely.
Austro engines used to be Midwest Rotary. Midwest were actually producing these engines in the early 2000's and when bought out by Diamond the disappearance of the engines caused the failure of several airplanes in Development including the Swiss Aceair and I believe the Solo.
Quote from Wiki:
Aceair ceased operation in 2004, and with it the Aeriks 200 project was cancelled. Ths was principally due to Diamond Engines cancelling the manufacture of the rotary engine the 200 was based around. Some assets of the company were purchased by a pair of entrepreneurs, and so the Aeriks 200 may eventually see commercial launch someday.
I was just about to order one at the time, the engines had very good power to weight ratio and should have been more reliable than a 2 stroke. Meanwhile, Diamonds priorities have constantly shifted and on the engine side most of the work was to dig itself out the hole created by Thielert. So if that had not happened, maybe the rotaries would have been brought back to the market years ago.
I think Diamond felt like it was being raped by Rotax (as does everyone else) and possibly thought they could get a competitive advantage at the bottom edge of the market with the rotaries. It would be great if they would get it together, but I fear that outside sales prices will be market driven thus no better than anything comparable in power.
Mistral had one running just fine on Jet-A. They are now back in business working on the gas version trying to get it cirtfied. Rotaries run well on very low octane fuels. In normally aspirated form they resist detonation with a long cold combustion chamber. Boosted rotaries act more like piston engines as far as detonation goes. Lynn E. Hanover