Meandmybike, I'm 6' and I generally fit a ~58 cm frame. A 50 cm frame seems exceptionally small for you both (excepting mountain bikes).
Exceptions in my household are a 56 cm crit bike (for quicker handling) and my son's French Fit 64 cm frame. I've never understood the reason for a French Fitting bike, but those that prefer one seem adament. I suppose it can account for those that prefer much smaller frames than what would be the norm and I'm unaware if there is a term, or nick name for that preference.
Brad