I GOTTA start checking Freecycle in my area, DANG!! Seen a few nice tank deals on Craigs list for awesome prices, but didn't have the money to take advantage when I saw them. I think the best free tank I ever got was a 29g. Got a free unfinished canopy that fit it some time later, painted it black and installed PC lighting and went reef in it for about a year.
Wait... come to think of it I got a 60g, stand and canopy with T12VHO for free too! Both tanks were given to me when I worked in an LFS. Forgot about the 60g cuz I let my room mate use it, then I sold it when he lost interest.
Keep us posted on what you do with it. From what you described, I can't wait to see it coming together. Post pics in stages as you set it up, from empty onward. It can be our next epic tank saga!!!