What I would like most as a TCO/TRM?Dispatcher)
A pen that writes in any weather and waterproof paper! In fact make it a clipboard with its own microclimate!
Did BA not recently experiment with red caps using PDA type devices for some parts of the job? I see a few flight crews recently using i-pad based software for check flights and the like, so I'd guess it's only a matter of time before some of the more adventurous ground handlers invest in some i-pads or similar for turnaround co-ordinators, but I don't think they'll ever be widely used across all the network in the major providers.
A radio that works would be useful though