Re: build no.2
Are you sure the rotors aren't as effective mounted opposite each other? I know the slots are directional, like the rims on some cars, but is there really any effect to the clamping action of the brakes? I don't really think there is. There's certainly an aesthetic consideration to having the rotors 'look' the same from side to side but braking action shouldn't be effected. The rotor on the front of my Switchbalde in on the right side and the Avids are supposed to be mounted on the left but I doubt seriously that it makes a lot of difference. I'm no expert on bike brakes but it just seems to me that when those calipers clamp, somethings going to stop.
As for drum brakes, I have no experience except for a drum/band brake I had on the front of a trike. It would lock up the front tire but it was only a 12" wheel with a skinny little tire with little road to rubber contact. I have no idea how it would perform on a larger wheel/longer moment arm.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"