That would be ideal but you will struggle to find a valve with that kind of bore ad if you made one it would be very heavy and would need a lot of power to switch it. You could also blow the end cap of your cylinder off by making the piston go too fast but I've never heard of that happening.
I would just use woody's QEV system as it is the cheapest way to get good flow. For the price of all that custom work you might as well go full pressure. also if you have access to lathes/milling machines (especially if they are CNC) it is not very difficult to make a high pressure ram.
Also, if this is for a flipper there is a maximum amount of flow rate you need due to how quickly you can accelerate the other robot. If its for your spike weapon then there will be a maximum due to the mass of the spike