I see what you're saying Zulu - Thanks for showing. It seems to me that life is full of compromises. It would be easy to incorporate a stop on a bottoming tap, or any other tap, but you are talking about a length of thread of less than 3mm. People who are happy to use a bottoming tap alone would end up with a nice neatly ended thread - those who prefer to use a tap lower down the order would need to work further in to the hole because of the taper. There doesn't seem to be one easy solution to this, but one thing is for certain - you can't please all the people all the time.
Hmmm. I have lots to think about