I built a fermentation room in my brewery that is basically what you are talking about. Outside temperature ranges where I am (Western Washington) range from 30 in the winter, to 80 in the summer. Not that big of a range, really. Plus the brewery itself, then the insulated walls of the fermentation room.
A coolbot may be overkill. I have my heater set at 71, and the A/C set at 75. All my fermenters stay about 66-68 degrees. New buckets do get up to 70 for a day or so when very active.
This is a new set up for us, and our first two kegs fermented this way were delivered last Wednesday. By Friday, the bar wanted two more kegs. (1/6bbl)