The new Mazda Renesis engine (RX8) is a good candidate, but not sure if anyone is aero rating this. Other recent projects:
http://www.wankel-ag.de/seite1_e.html
http://www.mistral-engines.com/index.htm
I think Norton still build drone engines in Gloucester (UK), but only found this site:
http://www.nortonmotors.co.uk/about%20us.htm
The main problem with the rotary is the need to supply oil to lubricate the rotor, which in combination with an awkward shaped combustion volume, means that it will eventually fall foul of emissions requirements. I think the general view is that if you need improved power to weight you are better turbo boosting a piston engine. This limits the appeal of the rotary for new engine designs.
The best site for the Mazda rotary is:
http://www.rotaryengineillustrated.com/renesis.php
My guess is that rotary offers maybe double power-to-weight over piston, but new materials technology forever helps piston power-to-weight. If you find out anything please post!
Mart
Edit: Wankel-ag.de site address