Decided to take a break from multires stuff and work on updating vpaint. This video shows first painting with regular vpaint, then the new vpaint. The old vpaint has trouble with high-res meshes, and you get that speckled paint shown in blue. New vpaint uses the same acceleration code as sculpt, which works around that problem. You can't see from this video, but it's also a good deal faster now. Note that this mesh is just an ordinary subdivided mesh, not multires; that'll come once these underlying changes are done.