This link shows how the Skymaster and Cardinal retract gear can be made for models. The full scale works the same way with the key being the angle of the gear leg pivot.
http://www.youtube.com/watch?v=mzjCox3tQ9k
The Hosteller plans I have seen do not show or reference retracts. The only comercial set to my knowledge is the Raymon Torres gear he sold as an option to his Cessna kit.
http://www.rtaerospace.com/