If you want to buy a bike that will feel like your 55cm road bikes, fuggetabout the 58cm bike. No matter what you do, it will feel different.fisherman said:
If you want to experiment with a Rivendellesque larger frame which will put you in a (potentially) more comfy, upright position, this bike might represent a cheap opportunity to experiment. However, most people trying this experiment go for a bike with a longer seat tube but the same length top tube. You can, as you said, use a shorter and/or higher stem to compensate. What size stem are you running now?
My 2 cents,
FBB