I have used but it is in Great condition the Gitzo model GH3750QR for sale, with this head you can use to take a paranoma picture too. If you are intercresting please give me an Email
You can see the link below in Gitzo how much they sale.in GitZo Canada.
http://www.gitzo.ca/product/0/GH3750QR/_/Series_3_Magnesium_Quick_Release_Center_Ball_Head
amd this is from Adorama USA.
http://www.adorama.com/GZGH3750QR.html