Note that the seattube angle can effectively lengthen or shorten the frame's forward REACH dimension to the tune of roughly .9cm per degree (and in proportion to frame size).
So my Lemond Zurich has very normal/average REACH for it's frame size.

Also, the headtube angle tends to affect how long of a stem will provide best handling. I find that, generally, a shallower headtube angle favors the use of a shorter stem, and vice-versa.
The fork's rake would also be expected to play some role here.

I have a Detel Marathon road frame with 50cm C-C seattube and 56cm level toptube. Angles are on the steep side. It fits me well (and handles well) with a mtb riser stem and long seatpost.