Can't you use the gifting option? I thought gifts are non reversible in PayPal? Could be wrong though, but is worth checking out.
Hmm, to be honest, I've never really used Paypal a lot, but I'm under the impression it makes no difference whatsoever if you send it as a gift - it can always be reversed.
I haven't read the full thread, but that is discussed here:
https://bitcointalk.org/index.php?topic=14632.0.
A quote from one of the posts there:
If they send you the payment as a gift (there is an option to do so), they CANNOT charge you back / get a refund.
Not true. They can fund their PayPal account with ACH, which is reversible. If they reverse this ACH transfer, PayPal will take back the funds.
Gift payments can also be made directly with a credit card, which is even easier to chargeback.