Yes, I use "upper entrances"...not to be confused with "top entrances".
I use these upper entrances when I unnaturally enlarge the colony by adding extra space, comb, and boxes, for honey production, etc. This may be for a period of 3 months or so for the late spring, early summer when supers are on.
I think the idea of extra upper entrances like having holes in supers, is a completely different discussion as compared to the promotion and use of year-round top entrances, and many times suggested in place of bottom entrances all together.
I actually have secondary holes in some my upper brood box. But the location is one that still allows a 75% of the upper box to trap heat. And over time, many bees will fill in this upper entrance since they are just hole in the box. Far different that the "top entrance" that some use which is constantly opened, the propolis seal is broken, and to which acts like a chimney letting heat out at the highest point of the hive.
There is also nothing wrong with one entrance....even if it is at the bottom. The hives, if properly positioned and slightly leaning forward, will not have an entrance completely covered in ice. I've seen some really bad ice storms, and within a day or two, the ice will melt away by the sun or the hive's heat itself. And I have NEVER had a hive suffocate. This whole idea that without a top entrance bees will suffocate or not have a way out of the hive is based on unpractical and situations that just don't actually happen.