Did you try an auto parts store - that is where I ended up finding the fine grits. or you can get 1200 online at: http://www.constantines.com/

The 3M Finesse It polish was the real key to getting a glasslike appearance - I found that at a Marine supplier. Use a wool buffing pad in your random orbit sander to apply it. You can see and get Finesse-It online at:

Link to 3M's site: http://www.mmm.com/market/automotive/product3.html

Link to site where you can buy 3M Finesse-it for $12.99 http://autosupermart.com/3m.html