Eames lounge cushion replacements  

The cushions often pop up on...
The cushions often pop up on ebay. I believe that there is a full set available at the moment. You may also want to contact Graham Mancha in the UK. He has always been very helpful to me in the past.
If you are looking for a brand new set of cushions perhaps Herman Miller can be of some help.

Why put brand new cushions on a vintage 60's Eames Chair?
They are expensive,overly puffy, and have no soul! Better and cheaper to find a nice vintage set on Ebay.That's my 2 cents! :0)