Unfortunately I've never found a great solution for ripping dvds on linux and I don't know enough about the protection on DVD's to attack the issue straight on. What I've found is one of the few things that works for ripping was using DVD shrink under wine to break the encryption and get the DVD as an iso, then using just about anything to rip the video from the iso. It looks as though there is a ubuntu package gddrescue that may be able to do that for you. But if you can't even get the DVD's to mount I'm not sure that even this will work. Generally after installing libdvdcss the drive will at least mount for me.
I know you've tried a lot of thing online, but this guy seems to have a walkthough specifically spelled out for your situation, getting DVDs to mount on *buntu
http://ubuntuforums.org/showthread.php?t=466248
The only thing I'd mention is that since Mythbuntu 9.10 is based on Karmic Koala just use the following where the walkthrough separates for different ubuntu versions
sudo wget http://medibuntu.sos-sts.com/sources.list.d/$(lsb_release -cs).list -O /etc/apt/sources.list.d/medibuntu.list
hth