Another thing I notice in at least some of the designs I follow, is that the wheelbase can be a fixed number across the whole size range, with the angles the same, so it's just a number for show. If you looked at those numbers you would be inclined to see really large frames as being too long when you generated real numbers.
I respect Jobst Brandt to the extent that while I may on not believe/understand everything he says, I am willing to swallow it whole when it follows what I want to hear.
I understand that even though he is more into road geometry than I am that he is a believer in the longest rear end wheelbase possible. I tend to agree, and would wonder whether there are any real points for riders outside the top few in the world in some of the designs that are out there. But if nothing else I am willing to believe it isn't worth worrying about a few fractions of an inch, unless you have very specific needs. I don't design around a number, I just design the rest of the bike and let the wheelbase take care of itself.