Well, here it is: the long-awaited video update in MAME 0.106u2. A few important notes about this release.
First, the new video system is not enabled by default. To enable it, you need to enable the NEW_RENDER makefile flag and recompile the entire project.
Second, if you previously configured MAME to use DirectDraw (which was the previous default), then you will get software-only rendering by default. You need to explicitly enable Direct3D rendering (-d3d) in order to get hardware acceleration. Software rendering is not very fast, especially at high resolutions.