Looking at the morph forms, I just played with her hands a little.  You can change the hands size bigger or smaller OR you can change just the palm, bigger or smaller.  You are right though, there seems no way to make the individual fingers bigger or smaller but, at least the hand size can be adjusted with morph forms.  I don't know how helpful it is for you in this case.

Quote - I am checking the bodypart scaling just now, and it is really odd - most bodyparts are scaleable, but some are not.  In almost all cases where there is a scale slider, it is only all three axes at once (one funny exception though!)  List of things that cannot be scaled appears to be:
Chest
Neck (there is a "thickness" morph though)
Head
Face parts (although 6 joints of the tongue can be z-scaled!  O_O !!  )
Collars
Hands and fingers cannot be separately scaled (I really don't like that, all V4s will have the exact same hands??)
Toes (rather irritated at that too)

Everything else has one x+y+z scale slider or another slider that does the same thing (e.g. feet).  I'm guessing the reason for this was the morphforms, but I don't know enough to understand why.