Id like to see an additional few blocks, if not a new addon, containing 2 and 4 round windows, a cap with a window in it, and some 3x3 tunnels with an adaptation block to 1x1
My reasoning? Simple; NASA style stations, but with conveyor connections!

An alt suggestion for the 3x3 tunnels, is one adapter, and then one panel for each tunnel subtype; vent, window, cargo access. Essentially allowing a tunnel to be built modular.
I'd also like to see in-wall beds if possible! I'd attempt modeling them myself, but i haven't any idea where to start