You can use DVDShrink
, which is a (free) Windows program, but it runs under WINE. It has a very fast MPEG2 to MPEG2 transcoder, and can backup an entire DVD (all menus, subtitles, multiple audio tracks, etc.) in less than an hour. Tell it to generate an iso image on output (the only option that works under WINE), then use k3b to "burn a DVD iso".