I found Airmaster Propellers at Oshkosh who has an electric prop setup for Lycoming 150-200 HP. Prop weighs in at 34 lbs, blades are made by Whirlwind. Airmaster has been in business about 15 years specializing in Ultralight, and LSA, and now entering the Lycoming market. I'm very strongly considering this setup for my 4.
Martin was very helpful, and lead time on their props is weeks instead of months. Their website is
http://www.airmasterpropellers.com
I'm not connected with Airmaster in any way. It was just one one of the more exciting products I ran across at Oshkosh.