Might I suggest the Really Right Stuff BH-40 Pro?
Its one I am going to invest in. $345 for the head...and RRS gets GREAT reviews from the likes of Moose Peterson and George Lepp.....Luminous Landscape and Digital Outback Photo.
Here is the site:
http://www.reallyrightstuff.com/ballheads/index.html#I think you will be impressed.
Find some good carbon fiber legs and your set..
Roman