I have an idea for a utility DVD that I want to create. (Something similar to Avia.)

This DVD would need to have extremely detailed interactive menus. It would be completely impossible to create this using one of those home-movie-dvd-creation-template-thingys that give simple indexing of the videos on the disc.

It would need to be created using the same kind of tools that the big movie studios use to create their most advanced and complicated DVD menus. The kinds of tools that they use to create easter eggs, and interactive DVD games and such. That sort of thing.

How is that kind of DVD interactivity created? What tools do they use, and are there publicly-purchasable versions of those tools?