I can't speak to the 'what gives' question you posed, but if you're looking for bike options that work with your numbers, the Breezer Venturi size S (45 ST, 525 ETT) has a 75º ST, 73º HT.
My size M/L (54 ST, 570 ETT) Venturi has a 73.5º ST, and 74º HT, so it's also an outlier by the numbers amongst the larger sizes. Trail, by the way, is 62mm (2.16") with the stock fork.
http://www.breezerbikes.com/bikes/specs/venturi-fmst