This version uses a different approach to try to accomplish the same results without parenting the boxes to the object being deformed.  The method has some inherent flaws which I think make it less successful than the other versions, but I thought I would at least post it for people to try if they are interested.

This does not parent the boxes, so they won't move along with the affected part.  A new button has been added to place the vertex boxes in the current position for the corresponding vertices.  That works nicely, and without parenting the script doesn't need to do all of the figure or actor zeroing at the outset.

However, this one suffers from the positional offsets with target actor rotation which beset the first posted version of the script.  In addition, deforming a figure (possibly applying deformations while any figure is in the scene) breaks body part welds - or at least causes Poser not to draw those welds.  So as you move a vert box, body part welds will seem to break and be restored.  This obviously indicates that Poser doesn't like the method very well, but it doesn't seem to break anything in my tests.

This type of error does make me wonder, however, if the very premise of trying to get real-time vertex deformations using a callback may be what foils Poser 7.  If that is so, it seems unlikely that any changes to GUI updates will reconcile the script with P7.  I hope that is not the case.  On the other hand, this one is untested with P7 and it may (althouogh this seems unlikely) not cause the same problems as previous versions. 

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Cage can be an opinionated jerk who posts without thinking.  He apologizes for this.  He's honestly not trying to be a turkeyhead.

Cage had some freebies, compatible with Poser 11 and below.  His Python scripts were saved at archive.org, along with the rest of the Morphography site, where they were hosted.