I realize this topic has been inactive for a while; but I concur that it would be a nifty feature to have (perhaps under a tools section of the interface. This is something that I have seen on a number of higher-end residential / commercial controllers.
The reasoning for this feature is that over time (especially with larger systems) valve boxs are often buried by growing vegitaation. This makes it very difficult to locate a specific valve box for repairs. (I live on several acres; some landscaped, some natureal. The way the valve boxes were originally installed does not make complete sense; since a valve box may be located 150 feet away from the zone it controls … very frustrating.)
On systems that offer this feaure; they mention that they rapidly switch the solenoid on and off; which creates a detectable noise to aid in locating the valve.
Not my number one requested featue; but something that could have saved me several days of hunting down valve boxes when I first installed my system.