This is something that I would like very much, too.  I would want it to calculate the current height and then allow you to input the height that you would like the character to be.  Would this also work on the clothes as well.  For that matter, could it be incorporated into an FBM (I use Wardrobe Wizard 2 to make adjustments in the clothing to morphed figures)?

I'm using Poser 6, by the way.