GEM has an unfinished vertex_array branch that allows for per vertex manipulations. I never found a very satisfactory way to deal with large sets of data in PD so the objects are very primitive.
I also would like to know, if that is possible.
It could be possible with gl shaders. but I am not sure and would like
to hear an answer from chris or iohannes.
max for example has a basic morphing feature between two shapes.
programs in which you can do realtime model animation on vertex basis
(or even higher level?) are as far as I know blender and gameengines
like ogre, to which you can talk through osc.
marius.