animation issue - different characters, same animation

I've been trying to find a good solution to this problem

(using TSMG, Maya, Mecanim)

I have some characters... all are different sizes, but the rigs have the same bone counts, names, etc.

I want to use 1 animation across all the characters - my research tells me that retargeting in mecanim is a good solution

problem I have is that when I apply an animation from a "tall person" the the rig of a "baby", the baby scales up to try and meet the profile of the animation it is using, which deforms the rig

has anyone encountered this / have any advice?

Thanks