I just finished 30x36x14. If it were near my single story house...it would dwarf it. It dwarfs my neighbors house behind it. It looks like a two story house back there. And even though I played by the rules (permits, more than doubled the set backs, talked to the neighbors that could see it) I still got complaints once it was done. One of the complaints the city got was "I didn't think he'd go that tall" (WTF do you think 14' sidewall means!?....Stupid neighbor).
Would I change anything about it? Possibly a wainscoting of the darker trim color around the base to help break up the height. Other than that....not a single thing. I absolutely love the size/height. It left me with enough room to build a storage loft and be able to stand up on top of and below it plus have enough height for my hoist.
For reference, those are 10x10 doors.
Just about finished.
From up on the loft looking down.