I have a shower in mine but its up stairs. I have an office, kitchenette, bathroom and laundry down stairs attached to my office, the urinal on other side really keeps the bathroom traffic to a minimum. I actually have 2 laundry tubs on the shop floor, number one thing in being able to keep neat is being able to wash hands easily and nothing kills a nice bathroom faster than greasy hands.
A tub needs to be slightly modified for a single handle faucet. I used cement block walls for fist floor and would only make a couple minor changes that are not much worth fixing at this point. I wouldn't have missed a pinch of space in office would have helped the bath/laundry room.
A lot of these pics are earlier, since changed a few things for convenience. I am not scared to remodel a little.
I also walk out of my office to use urinal in the shop. When I lived upstairs I was only there for few night hours. It has shower stool sink room directly above the one downstairs. There are actually 4 sinks, 2 stools and a shower hooked to this spot. The tub location in the pic is about perfect, its about 20 ft from the water heater is only downside but I ran only 1/2 pipe to speed delivery a little.
Its hard to see here but office door is to right of shop entrance.
All this is a major main fukkup I see in many garage designs. a lot of this kind of thing looks great on paper but works out differently in the end.