You CAN make morphs quite easily (in fact I know several artists including those at DAZ that do exactly that!). What you cannot do (at least easily) is create a morph AND a displacement map at the same time. You have to create the morph first and then create a displacment map off of that (after removng superfluous polygons). Hell a search in google for "compose zbrush full body morph" will give you a tutorial for doing just that (a full body morph using zbrush and the free compose utility).