I am 6 foot 4 and have both 4 post and 2 post lifts in a stick frame garage with 12 foot ceilings, I have 8 foot fluorescent lights throughout. I normally work on my cars when lifts are fully extended (to keep from abusing my bald head). It is possible for a 10 foot ceiling to work if you are shorter than me or dont mind working in a bent-at-knees position. I actually have a friend that put a 4 post in a garage with 8 foot ceiling. He works on his cars while seated on a rolling mechanics chair and seems to have no problems at all.
You must also consider the height of the vehicle you are working on. Cars are normally shorter in height than trucks. Therefore if you intend to work on trucks, the cabs may limit the height you can raise the vehicle, limiting the space you have to work under the lift.
If you intend to do heavy work (replace rear ends, transmissions, etc) i think you may find a 12 foot ceiling more accommodating.
Hope this helps......
Phil