stu, still workin` on my first cup so the ol` brain cell ain`t up to speed yet... but the front spindle of an old camaro or such would be severe overkill for the top wheel and 15" rims are a dime a dozen. i could see a double pillow block and shaft set-up working for the drive wheel.....maybe the rear axle turned down to fit the pillow blocks?.....do you have access to a metal lathe? ........man this thing i`m envisioning would be heavy!! better quit typing and drink coffee ...tod