Here is an idea from Randy Lervold. I would consider this on the 4 vs the servo mounted in the elevator. Some research and noodling required.
http://www.romeolima.com/rv3/rv3works/airframe/airframe.html#ElectricFlaps
Does anyone have a copy of the electric pitch trim installation instructions from vans that they could post or send me? Also, what is included in the kit? It costs $325 from Vans and the servo, push rod and clevis are less than $200 from Ray Allen.