Great bike hack on Instructables from Maxwell – “How to Build a Tall Bike, one that you can stop safely, and could be construed as street legal in most places. With this method, you’ll be able to stand over the bike, allowing you to hop down easily, have two brakes, a full complement of gears, And have a better riding position than two bikes stacked on top of eachother. You’ll only destroy one bike, The top portion is bolted to the bottom bike, so if it breaks, or you get tired of it, the bottom bike can be reverted to normal. All in all I think this makes for a suprisingly sane tall bike. Not that you’ll look any less the madman riding it through traffic.” Link.