Try www.usplastic.com
FYI a chat conversation I just had with them:
You're now talking to Alteesh from 'Customer Support' The topic is : clear acrylic circles
Alteesh> Hello, My name is Alteesh, How can I help you?
Parker> do you happen to have the ability to cut custom clear acrylic circles? I would be looking for something just smaller than 3 1/2". I see you have 3" and 4" in stock.
Parker> Also, is there any chance you would have any solid colors available, rather than just clear?
Parker> Item #44185 and 44186
Alteesh> Yes we can possibly. You would have to contact our quotes department via email or fax to send the request in.
Parker> Okay. I can do that. Thank you. Do you happen to send out samples of a product? Like, sending me one of the 4" disks so I can sand it down to 3 1/2" and test the material?
Alteesh> I'm sorry we do not have a sampling policy. In place of that we have a $5.00 minimum order.
Parker> Okay. That will work. Thank you very much for your time. I will make a minimum order, test it, and then contact your quotes department. You have been very helpful. I appreciate it.
Alteesh> Thank you for using our Live Chat. You can rate this session at the top of this window. Have a nice day!
Parker