I did not get any reponse to this search for weighted, balanced palettes, so I thought I would post my own research.
This place has a version called the "Starving Artist" which is the same as the very expensive one except for a slip and patina, it is the one I purchased and it is great. They were very nice and shipping was under $9.00
http://www.willowwispfarmstudios.com...ets/frame.html
Lee Boyton makes his own palettes which are just about the same design as the ones above. They are priced like the upper end one but the shipping was $20.00.
http://www.leeboynton.com/
Bill Whitaker has also created his own palette based on an English design he found the original in London. He likes his smaller than the ones above, and they are huge. I am sure he would share his design with you or give me permission to share it for him.