I have a JR (which is 33X26X16). THe Graupner above is (32x16x33mm). If you look at the dimensions of most 1/12th servos they are usually 2-3mm larger per side (especially length and height). I'm talking the next size down.

Like this specifically:
Sanwa-HR-141 (27x12.1x30.5mm)
http://www.redrc.net/2011/04/sanwa-h...tal-112-servo/

Or the KO Propo PDS-3101 (30x12x26 mm) (Not really per no bearing)
http://www.kopropo.com/america/index...104&Itemid=150

Heck I even heard of someone using a real micro servo once like the HS-5065MG (24x12X24). That might have worked for their purposes, but I wouldn't trust it to have enough torque.