Okay, I figured this would be a fun game, here's the Gear Form:

Gear Name:
Gear Type (As in Board, Skates, Wheel, Yacht, Bike & Air Ride):
Gear Change One:
Gear Change Two:
Gear Change Three:
Description:
Character's that can use it:

Here's one:

Chaos Spear
Board
Gear Change One: Grind. (10 rings)
Gear Change Two: Air ride. (15 rings)
Gear Change Three: Bike. (20 rings)
Description:
A board that looks like a red spear. It is the only gear that can be every type at the same time.
Can only be used by Shadow.
Press the following button combination when you have selected sonic & are about to select the gear "chaos Emerald) to have super sonic riding this gear;
Controller forwards: A+B.
Controller sideways: A+2+1.
Gamecube Controller: A+L+R.