I might try the oil again but I know from past experiences that although it provides some degree of coloration on the outer crust, it won't go as dark as John's...or Totonno's for that matter.
Mike, although I think your pies are already better than John's or Totonno's, if you really want to emulate the appearance of their crust, put the cheese under the sauce and use the broiler during the bake. If your plate is towards the top of the oven (6" or less vertical space), then about 3 minutes of broiling should give you that much color- assuming that the broiler stays on. That much top heat will normally brown the cheese too much, but if it's under the sauce, it should be fine.
Like I said, though, I think John's is a step down from what you're doing- unless, of course, you just want something different.