IIRC, when we've stayed in the studios (at BWV), we had a small coffeemaker. Believe it was a 4-cup size. However, others have reported that you may request a full size coffeemaker from housekeeping if the smaller one won't "meet your needs" (LOL)!
Just stayed at Bw last week and it was definately a four cupper! We also had a one bedroom attached with a twelve cupper, which made for a god joke as the real coffee drinkers were in the studio!
We were there the end of March and had a 10 cupper. If you have a little one and want a big one just ask the desk. I'm sure they will bring you a big one or visaversa.
We had a concern about the coffee pot on our first stay in a VWL studio so I did some checking. I was told the 4 cupper comes standard in the studios and you just need to request a larger one from housekeeping either in advance by fax a few days before or when you arrive. You can also request a toaster if there is not one in the room - as I was not sure if they were standard in a studio. Some rooms will already have the larger coffee pot as they are requested often.