Hi Sneaky,
I recently built a turntable that sounds like it is probably similar to what you are looking at making using a large diamter ring style turntable found here.
http://www.mcmaster.com/#18635a52/=94mzu6
If you'd like more info. let me know and I will try to get you some pics. etc.
Good Luck! BTW- You came to the right place for help!
