You guys that were talking about using the throttle-by-wire from the Renesis.  Eggenfellner (Subaru) is using a similar setup on his H6 setup and sells an "electric throttle".  Looks like either a linear a slide pot or a LVDT. 
 
http://tinyurl.com/abf2f

Pretty clean install.  I might actually have to consider this.  Now, I have no idea if this is the same animal as the Renesis units.  Might be easiest (and cheapest) to just go to the wrecking yard and get the other half.
 

Mike McGee, RV-4 N996RV, O320-E2G, Hillsboro, OR
13B in gestation mode, RD-1C, EC-2