These are the official measurements given out by Jun Planning/Groove. There are some errors, but for the most part they are correct.
Pullip has had 4 different bodies, each with different measurements.
Dal/Byul have the same measurements
Taeyang/Namu have the same measurements.
Isul does not have an official measurement chart yet, but I measured him and put the results at the end.
Head Girth: 25
Neck Circumference: 3.75
Elbow Sleeve: 4
Wrist Sleeve : 7.5
Shoulder Width: 6.5
Back Length: 5
Leg Length: 14
Foot Length: 2
Foot Width: 1
Foot Girth: ?!! Wtf? I could not figure out what this measurement was.
Leg Girth: 6
Arm Girth: 3.75
Isul and Pullip are generally compatible with clothing. For more on this, check out this blog post