Last fall, I had a 50'x90'x14' tall steel building built. A have plans to add a "porch" across the front to park trucks and a shed along one side to store equipment under. Mine has at least 5" of fiber concrete and the roll insulation which is fiber reinforced to help prevent sagging. I have a 10'x10' insulated roll-up door on the far end and a 12'x12' insulated roll-up door with power opener on the end closest to the house, with an insulated metal walk through door going into the office.
For power, I have a 400 amp 3-phase (240v) main panel with two 100 amp single phase sub panels. I would highly recommend 3-phase if you have it available... I was lucky!
Lighting is where I really "shine". I do electrical work on the side and have acquired hundreds of used light fixtures. I have kept and "restored" some of them specificly for use in my shop. I have 118 4' 2 and 3 lamp fluorescent fixtures in seven rows. I can switch each row at mid-shop. YES, it is overkill, but it is BRIGHT when I want light!
I hav an office, bedroom, bathroom and climate-controlled work area under construction, in which I will install central heat/air. I will also install a hanging propane furnace, just to "knock off the chill" in the main shop area. I may supplement it with a burnt-oil furnace.
I would HIGHLY recommend to any of yall who are planning a shop to think ahead to the future and "rough in" plumbing under your slab before you pour concrete. Mine is equipped for my "to be installed" toilet, sink, shower, clothes washer, water cooler and washbasin sink.
Go for OVERKILL on power supply too!
On another note, commercial cieling fans sure are nice too!, As are the insulated roll-up doors.