Dragon(DML) produces Sdkfz 250/9. You can check this out at this site( I think the hull interior is made up of after market parts)
http://www.skalman.nu/third-reich/model-dragonman-sdkfz250.htm
Tamiya also produced one back in around 1979. The 20mm turret is same as the Sdkfz 222 amour car turret. Tamiya one is no longer in production, but you might find it from time to time in model shop. Dragon one should still in production. Hope this helps.