Very interested in building one. But I would want to do it on the open VESC controller (with integrated IMU - about to release I think). My DIY dream machine currently looks like: 18 inch wheel, VESC controller + bluetooth interface, some sort of modular battery design, waterproof, capable of gotway msuper speed (after it's well tested and trusted at such speeds). Thinking maybe individual cell holders of 18650 cells. But maybe not on the first version.