Awesome. That should put a well-deserved end to the "Nobody wants a single disc with the movie and the extras" and "30GB ought to be enough for anyone" talking-points.
Now we can focus more on the "Retrofitting existing DVD production lines to make HD-DVDs is much cheaper than going for something with a different layer structu ... uh." and "We don't need a hard-coating because the data layers are so far below the surface". Humungous cost differences right there folks. It may just have shrunken but it might still be more than one cent.
Any word on compatibility with existing drives/players?
Until it's submitted to the DVD forum and approved, you won't know about player compatiablity. Only exception being, actual words from a MS or Toshiba insider.