Where can I find an Eames La Fonda Base?  

keep searching
you are just going to have to keep searching for one with a beat up upholstered seat on ebay and craigslist, they are out there. I was at a flea market this past weekend and a dealer had one with a nice seat but a badly pitted base which he wanted way too much money for.

bidding
I've bidded over a dozen times on la fonda bases. Don't low bid. These bases are more expensive than the average HM base. I've lost out every time because I was trying to win the base at a low price.