RE: small rotating retracts
Smallest commercial set i knowof is the Hobbico set for .40 size airplanes. Depending on the model... they MIGHT be OK for a .25 size.
You can modify straight type retracts into rotating type if the strut is held in with a setscrew... and there is room to insert some wheel collars on the strut to keep it from sliding up and down. (deleting the setscrew. This is essentially how the Hobbico's work.) A couple of ball links and a 3rd wheel collar are used to actuate the rotation. (it would take some better computer drawing skills than mine to show how...)