I like the cabinet betweein the basins, defining each space. About windows in bathrroms..our MB has two large corner windows, with the tub in the corner and the glass shower nearby.making both on outside walls...in the winter, it's the coldest room in the house..makes you dread crawling out from under the covers in the mornings..so rethink windows and the area in which you live.

I am assuming there is a vent since there are no windows. I hate having to open windows and close it every time i shower. It brings in cold air and its no fun when you want to shower at night. We have no vent and our window is mostly out of necessity to vent air. We opted to install shower farthest from window for that reason. Why do you want to add a window if there is no other way but up? I like the windows for scenery if there are great views outside and still offers privacy, but not if i only see skies, i'd prefer a skylight.

I have two bathrooms with no windows so I did have to go up! I put skylights in the ceilings of each and love them. Mine are Velux and open by a motor. In addition I have shades between the panes of glass which are also power operated and if it starts to rain, doesn't matter if we're home or not, a rain sensor closes them automatically. I've had no problem with leakage but you do need to keep your room well ventilated during showers so as to eliminate the possibility of condensation.