ANOTHER vote for the Ries A100 legs and A 250-2 head. It holds my 12x20 Folmer & Schwing quite well. I've used ALOT of the various options over the years, Giottos legs, gitzo heads, berlebach, etc etc ... and the Ries combo is the greatest thing for the ULFer since sliced bread, pure luxurious goodness.
Heavy as all get out... but if you want low on the weight, dont shoot ULF... its Ultra Large Format not Ultra Light Format.
Also, someone posted a link to the Badger website to buy the Ries A2502 head. Its about $70 cheaper at the View Camera Store. I bought mine from there and Fred gave me a free square of leather to glue on top the head.