I've got a number of frames hanging in the garage and was wondering if I could do something like the Rivendell Quickbeam. The QB uses a road double crank with a cog to give you two speeds; four if you flip the rear wheel.

I wondered how good the chainline was with that setup; probably good enough or Rivendell would've not put it on the market.

Then I see the Surly Dingle cogs and thought; what if I used one of those with a road double crank and gave myself four possible gears without even flipping the rear wheel.

I am thinking of using a Sugino RD crank with a 48 outer ring and either 46 or 44 inside ring. Then putting a 17-19 or 17-20 Dingle on the rear wheel. Going inner ring to inner cog or outer ring to outer cog should still give me a straight chainline but what about outer ring to inner cog or vice versa?