Model Railroading > Cab Signalling

Out of curiousity, does any technology exist for cab signalling on DCC?  I know Digitrax built that functionality into their larger throttles, but I have not seen any notice or device that takes advantage of it.  I've seen homemade systems integrated into stepper block DC cab control where the cab signal is mounted on the wall or a base unit for the operator to reference,  but never a mainstream system with the signal actually displayed on the handheld.  

Thanks,
Sean