iPhone Duo is here. Here are 9 startup ideas I’d build for it: 1. Mobile sales room: prospect profile on one side, live call notes + objection scripts on the other 2.Pocket CAD for trades: plumber/electrician sketches room measurements with Pencil, app converts to parts list, code notes, quote. Beats Autodesk. 3. Contractor estimating app: blueprint/PDF on one side, materials calculator + margin controls on the other 4. Jewelry trade in app: customer sees instant offer, buyer sees…