Have you looked at Mohawk lifts yet? They are not tall and the limit on height is clearance with your lifted vehicle to the ceiling, not the lift it's self. they have a hydraulic line that needs to go from one side to the other, this can even be put in the floor, or made and bent to follow your ceiling.
http://www.mohawklifts.com/wp/automotive-lifts/2-post-lifts/system1/They're not cheap new but in my opinion look to be the most robust of the lift choices, and made in the USA, and can be found used pretty regularly at better prices if you have time to shop.
I've seen lifts outside and I think that's much less than ideal. If the weather is bad you're limited, if the project is long and weather comes you're out of luck again. The lift deteriorates in the weather too.
If a lift is important and you're building the new building with one in mind I'd sure put it inside, even if it cramps space a little at least you can use it on your schedule not dictated by weather or seasons.
