Eames lounge chair  

To my knowledge
...there are no knock-off cushion replacements. But if there were, based on the quality of the knock-off chairs I've seen, I don't know if they would be worth buying.
If you need to replace the leather on your cushions, you can always do just that. Replace the leather. The upholstery shop I use redoes Eames lounge chairs regularly and all they need is the fiberboard backing to make a new set of cushions.
You can have get new foam or down filling and new leather to restore your cushions if yours are beyond repair.

I'd second what Pegboard...
I'd second what Pegboard suggests: if you do not want to buy new cushions, just have the old one's reupholstered by a good upholsterer. I know my guy regularly does Eames chairs, too.

I think
that is the path I am going to take. Was just quoted 600-800 to get the leather to what they tell me will be "near new" condition. Does that seem like the correct price? They had me send pics of the chair to them showing the leather damage. They state that the leather that can be salvaged will be repaired/re-dyed etc...
Are either of you in NYC? Can you recommend a place? maybe I can send the cushions out. Would rather have it done by a place that has done others eames chairs as this place didn't even recognize the chair.
Thanks

you should be able to ge...
you should be able to get nice leather for a full hide for $225.00 and it should cost you no more than $950.00 for labor for a complete redo . check the web you can send the cushions and arms in one box to some of these places. shipping should be no more than 50.00 bucks.

one more thing Dying ...
one more thing Dyeing leather would not be my first choice only when you have to, or need to match a small tear.

Why not buy a new Eames Lounge Chair?
You could get a brand new Eames Lounge Chair that will last another 20 years. In the next couple months Herman Miller will have another sale, the last one was early this month.

You might also try repair
A friend of mine had her Vitra Eames lounge repaired because she couldn't find new Vitra replacement cushions here in the states.
The chair was in some serious need of help - cracked, some of the finish was flaking, and the seams had torn on the seat cushion.
I found her a guy who repaired everything - it was amazing! It didn't look brand new, just like she had actually maintained the leather from day one. And i believe it only cost her a few hundred bucks.
Might be worth a shot?

screw new
My old time-life lounge is tearing and I am considering gluing in a fabric backing to close the rips and radically slow entropy. I have read about this in various places. Anyone tried it?

.
To the OP. (edit) It is worth repairing with new leather.
Takes a bit of research but look for someone who is familiar
with the chair. ...I'm traveling so i don't have my list of repair
shops handy.
For a home repair use your friendly 'google'
Search 'leather tear repair'
You will get hundreds of hits!
I repaired mine with a version of this method...
(a youtube instructional)
http://www.youtube.com/watch?v=-qe9wtJiRcs