The market for these aircraft is substantially larger than most anticipate. Airbus currently has orders for over 600 new A320 Neos and the electri taxi systems will be coming to market for narrow body aircraft both new and retrofit. Safran Honeywell are making a model for the main gear assembly and Wheeltug is making one for the nose gear. Safran currently has made no ground on the development since last year at Farnborough where they showed the same display as this year in Paris. WheelTug is already conducting on aircraft testing with development in the final stages. Both systems are designed to pushback from the gate and taxi all the way to the runway via an electric motor in the wheel powered by the APU. The wieght on the system is nuetral when considering the amount of fuel saved from carrying on board for taxi time. You can literaly depart the gate with min fuel for the flight and carry more bags and pax for a longer haul carrying 45 minutes less worth of fuel.
This system is becoming such a big hit with the number crunchers everywhere because of many reasons. The Eco reason on emissions while on the ground is greatly impacted and the life of engines is extended. Also, time is a big cost for airlines and when you consider the time between push back and spin up of the engines, the time saved adds up quick.