So this is my current equivalent of your proposed bike -
[IMG]
7/6/2017 2nd version by
Russ Fitzgerald, on Flickr[/IMG]
And in no particular order -
Exage is good stuff, or at least good enough. The pictured DB Venture came stock with Exage Action road stuff, but with a 400LX crankset with steel 28/38/48T Biopace rings. I have realized I don't notice that they are Biopace unless I look down at them while riding. I have ridden bunches of stuff with Exage parts and my observation is that it works about as well as anything else Shimano makes, it's just not fancy or expensive. According to Velobase, they're about the equivalent of Sora or Tiagra, and were considered good consumer-grade stuff but not race-worthy. Pffffft. I've read posts where people talk about Exage rear derailleurs being prone to breaking, but nothing solid. Then again, mine came to me originally with a SunRace replacement. Then again, it also has a bent derailleur ear, which makes me suspect the original was done in by operator error or misadventure and not by spontaneous failure.
Oh wait, there's this -
http://www.bikeforums.net/3246439-post9.html which shows Exage being above Acera X ...
The cantis should work just fine with conventional road levers, it's V-brakes one has to watch out for.