DVDlab PRO is exactly the software I want. Complete control over DVD menus, motion menus and audio as well as subtitle streams and multiple audio tracks. It's US$199 though, which is a little pricey. This is something I'm really enjoying. The non-PRO version is US$99 but doesn't support multiple audio tracks or subtitles which I'd like to play with. I can't seem to find a trial version of DVD-Lab Pro.
Although I don't really have time for this stuff... ;(
Ultimately I'd like to build a DVD menu for the band's video DVD-R when it's finished including lyrics as a subtitle track and possible something silly like a band commentary and maybe the full EP as audio tracks somewhere on another menu.
I've also been playing with putting some live shows I've recorded (friends bands, with permission, for personal use, calm down Sony*) onto DVD with their hand-written setlist as the chapter chooser. Much nerdy.
It's so cool that it's so easy to do all this stuff.
* I find it rather funny that the little stickers you get with icons on for sticking to your Sony Digital 8 tapes (party, wedding, sky, friends, landscape, animals) do not include anything that represents music. Personally that's about all I'd do with a video camera, tape friends bands, tape my band, maybe go to the zoo or tape a wedding or something. I feel they almost deliberately set the tollerance of Sony video camera built in microphones to a level that live music will distort. Lucky I know how to synch my Sony minidisc (haha) audio with my recorded video.