I don't think there's much out there anymore in that size. I'd scratch build. Here are plans that are readily available:

RCM - Basic Bipe (36 inch, boxy and easy), Airmeister (42 inch mini Aeromaster; would work if built light), Jungmeister or Tiger Moth (Whitehead).

Northrup Plans (see ads in Flying Models) - Galloping John, Bitty Bipe, Beech Staggerwing, Waco (the last two for .25 two strokes with simplified construction but still good scale outlines).

Model Aviation - Gypsy Moth (50 inch).

Flying Models - Dreamer (38 inch Pitts type - would need to be built light).

This is just a small sample of what scratch building can open up for you. Jim