Indeed similar devices are currently available. I know about one manufacturer:
but their stuff is analog and incredibly overpriced. Since they have no concurence, they set the prices. If I would sell my digital trigger, it would be something around $700 including two laser triggers and cables. But I am not quite there yet to set prices.
Aggie, you dont need 4 cameras, that's just an option, which cost little but would be an advantage considering the current triggers. If someone wants to capture an event happening once in a lifetime, it's better to set up multiple cameras if you can afford. Many can; I know people owning 3 Nikon F5s among many others, with a bounch of lenses. Indeed protecting the cameras & lenses is a challenge but this is something photographers should sort out, considering the environment they work in.
Setting up the trigger would be as simple as setting up a digital alarm clock. I already designed the user interface and showed to some of the fellow people over here. They said that's transparent.