I don't actually know of anything that does HDDVD menus specifically. However, a number of products, including SageTV's HD200 box do handle DVD and BluRay menus. Of course I don't recommend that box for stand-alone use. Clumsy/awkward UI for that.

It's definitely a lot faster/convenient to rip movies wholesale, including menus, but it does of course take up more drive space if you don't pare down the extras and fluff.

Maybe once those fabled and long overdue 3TB drives finally come to market things will start looking more capacious for my cinema collection... I've ripped a number of DVDs, but the vast majority of my collection is still sitting only on silver discs. Kind of hard to play them back when I don't have a DVD player connected to a TV anywhere in the house at the moment.