Hi Rob,
You can get the 405 Geared Head off of ebay for about $600..
that's something i wish i looked out for when I bought mine!!
buying it locally it cost me nearly $900!!
you can get its baby brother, the 410, which still holds 5kgs; for about $300 on ebay or $400 locally
I'm not unhappy with it, it is still rock solid even with my 400mm f2.8 hanging off it. A vast improvement on my 25 year old Slik that my dad gave me when i was 14.. That thing used to jiggle like a bowl of jelly haha!