After having a small cramped space for reloading in our previous home, when we built our condo I made specific requests of the wife for large enough space in the basement. She said she would design the upstairs (she is a decorator), and I could design the basement as long as I provided for a bedroom, full bath, and family room. No problem.
My loading room is 21' x 12', with a 4'x7' all concrete walk-in vault in one corner. I built the work surface at counter top height in a "U" shape all around the 60% of the interior of the room, I have about 30' of work space counter top. I used various base cabinets and 2X4 framework all tied together with 3/4" plywood topped by 1/4" masonite that I put several coats of Poly on.
Cleaning and repair work space.
Load development work area, with turret loader.
Dillon loading station and Shotgun loading station.
Back wall, where vault is and shelving for gun cases.
On the small remaining part of a wall to the right of the cleaning station I have a rack to hold my fly fishing tackle and a cabinet to hold tying supplies. I've been in it 11 years now, and I wouldn't have done much different. Just outside this room is my regular workshop, with drill press, compound miter saw, gig saw, work bench , etc.