RatDVD is a very similar format, based on your description of Matroska.
On the point of ripping though, people do sometimes mean different things, though obviously it always involves copying the files from a DVD to a hard disk - you can get 'ripping' software that just removes the encryption and copies it to the hard disk in exactly the same format, just without the encryption. Most DVD playing software will happily play the files from a DVD copied onto a hard disk.
However, sometimes people mean taking the content (protected or not) and converting it into a compressed format, such as XVID. There's now a lot of software available to do that, particularly since the arrival of the PSP, though clearly any software you buy in a shop isn't going to handle cracking the encryption, it will only do unencrypted content.