Would any spindle allow for a dual drivetrain? I wanna put drive side cranks on both sides--I'm thinking BMX cranks since they have left side drive bikes. And then I would have a flip flop hub on the back with two freewheels which would make it a pseudo fixed gear. So could I just use a regular spindle and have really tight clearance on one side? I could try road cranks and put the chainring on the outside maybe.