Mark not to worry I've already got a twenty ounce version that I made myself last Christmas. When I bought the magnets from Forcefield I used one on the cup and it's held up well. Remember way back in this post when you first started the cup r&d that I wondered how long it would take before you got the hard drive magnets out?
Now a fair market price for a plain jane twenty ounce cup with a magnet base. I would say 6-8 dollars with no logo on the cup.
You could name it the Chalkey jr. or better yet the Chalkley poppa bear,Chalkley mamma bear and the 20 oz Chalkley baby bear Forcefield cup. Can you tell I've got kids./w3tcompact/icons/smile.gif
Now the next thing that has to be perfected is the dust lid. I use a plastic small bowl that I swiped from the wife. It fits loose over the cup and keeps most of the dust out.
gordon