Steve, I'll attach a link to a thread I started about it.
http://www.sawmillcreek.org/showthre...6427-Shop-pics
It's L shaped, I have 10, 6 bulb fixtures for it, 2500ish square feet. If it wasn't odd shaped, less would work fine. It's still in construction, will be for a good long while still I think. My contractor is pretty busy
We have them in two other shops on the farm too, one 60x80, one 40x60. 10 fixtures in the bigger building, 8 in the smaller. The smaller has 12 foot ceilings too, and it is nice and bright.