Having an item to see how fast you’re going in a condo or the plaza would be nice. I think it’d be a good way to visualize the difference between walking, running, flying, bhopping, and rocket jumping.
I also think having an option to switch between something like the Accelerate and Ball Race styles would be cool too. (and maybe the Ball Race one could use your inventory HUD color?)
I imagine it working like the Radar milestone from Virus, where you just drag it into the weapon or wearable hotbars.