This is trueness;… there seems to have been a missing link between loaded touring bikes and race bikes, from what I’ve seen, back in the late 70’s and 80’s which Surly and Soma have exploited with their Cross Check and Double Cross designs. As nice as they are, I have a hard time paying the retail price for their frames when an entire good quality steel framed bike can be had for half that. The problem is that finding the vintage bike that meet your requirements will require some compromises that only you could make. You could go with a full-on tourer and strip it down, but you’d be left with a sluggish bike that was designed to come alive only when loaded back and front. Or, you could try to MacGyver a sport frame. I have no answer for you, but I’m going down the same road. Among the bikes that are currently in my radar are the Bridgestone 400 and Univega Gran Turismo. There are obviously others hidden under some magical rock somewhere, but only you can do the homework to find it.