I was thinking bvhtree and kdtree could accelerate python commands,
basically the compiled native code of the tree hands the data to a compiled command, so you never iterate over the data in py.
using distance of returned vertex and lerp, color etc one can paint and sculpt, but some sort of method would,need to be designed to pass args that are like functions.
vertex.XYZ = vertex.XYZ.lerp(vertex.XYZ+(vertex.normal*.height),radius-distance)
is sculpt with flat falloff