The 700r4 with it's 0.70 final OD ratio is a great choice for your application IMO. You can put some rear gears in for some added pop in the lower gears and still cruise at decent rpm's for economy and less wear & tear on the engine. Pick out your rear tires for the look you're after, then select your gears based on your torque & HP curves, calculated or dyno'd and your tire height. I'll leave the engine magic to others who can give you specifics on your plan, and possible options.