I spent all list night experimenting with a sudden idea I had for using morphs instead of a separate base figure to make V4 into a child.  The advantage?  Well, the way I see it, if you want to make a juvenile version of a V4 character, you have one of two choices:

1)  Open up Laura, load her morphs, pull up a reference render of your adult character, and spend several hours of trial and error morphing Laura's face so that it resembles the reference shot as much as possible (with allowances made for childlikeness)
2)  Buy a good morph transfer/conversion software package and use it to convert the morph setitngs from Victoria to Laura.

The first option is tedious, the second is probably like a root canal for your wallet.  Here's what I did in a nutshell.  I used standard V4 morphs to narrow the hips and flatten the breasts.  I also widened the waist and shrunk the gluteus slightly.  Then, I made a pair of INJ and REM poses based on the result.  I opened up my V4 character and applied the INJ pose.  Next, I selected "Create Full Body Morph" and named the morph "Pre-Pubescent."  I then applied the REM pose.  In effect, I turned the binary morph pose into a gradable morph (this is useful for creating a young teenager).

The only real inefficiency is that I had to do the same process with the V4 Bodysuit since it doesn't magnetize well to custom morphs.  Beyond that, the "Pre-Pubescent" body morph used in combination with the "Young" head morph, "Head Size" FBM, and figure scaling pretty much did the trick.

This is an example of the result: www.renderosity.com/mod/gallery/index.php

There, you see my character, Francesca, at the following ages from right to left: 7, 14, 21. 

The 21-year-old is the unaltered figure. 

The 14-year-old has the pre-pubescent morph set to 0.5 and the "Young" head morph set to 0.3.  She was also scaled to 92% of adult size. 

The 7-year-old had Francesca's body REM pose applied before the pre-pubescent morph was set to 1.  She was then scaled to 73% of adult size, and the "Thin" FBM was set to -0.2 to keep her proportional.  The "Head Size" morph was also set to 0.1, and the "Young" head morph was set to 0.5.

The only thing I'm not sure of is whether or not I need to flatten the breasts a little more on the morph.  The 7-year-old's chest looks perfectly flat (rounded, but not bulging at all) from a 90-degree (i.e. lateral) angle, but from the angle of the sample image, I'm not sure if it looks quite right or not, and if not, if it's a trick of the eye or if she really is a bit more well developed than she should be.

That's one of the reasons I decided to post in the gallery and here asking for honest critique.  So please let me know your thoughts on my procedure, the results, or both.