The closest I've come was with a Lanier Laser 200, and a similar plane, their plastic ARF TR260. These planes have symmetric airfoils and the prop shaft is on centerline.

Both planes, when rolled inverted, need just a thought of down elevator. More than that makes it pitch up. I attribute this characteristic to (1) the design, with symmetric airfoils and centerline thrust, and (2) balancing properly. Or perhaps putting the CG awful close to aft of the proper location.

Good luck,
Dave Olson