I'd like this too. If you look at Alpha videos and look at the way the Kraken works, he currently pops up and down on a pre-set cycle, so if you have him hidden behind a turn on a coaster for example you might not always be guaranteed to see him leap out when the car passes. To be able to trigger him as the car approaches would be excellent.
Perhaps this could work by being able to lay a 'trigger' piece of ride track and then linking a node to a nearby animatronic object (I'd like the option to trigger objects of varying distances from the ride track).