Absolutely it can be built into an model airplane engine. IIRC early motor cross bikes had centrifugal /mechanical power valve systems, where the road bikes were electric. Three types I'm aware of are the rotary type of the early Yamaha's (RD'S,RZ's, TZR's), multistage guillotine (RGV250), and single stage guillotine (TZ's). I can say in all cases while the bottom ends are improved, the transition wasn't 4-stroke smooth on any of them but that could have been purely due to other design considerations.

Don't forget Yamaha 4-strokes motorcycles have had their EXUP system for 20+ years which is a valve to vary exhaust backpressure.

Apart from weight, I'm surprised this hasn't/wasn't offered by OS on an F3A engine but I guess Fuel injection didn't require new crankcase molds where power valves do...