I just thought about the following:

You open one regular paypal account
http://www.paypal.com/cgi-bin/webscr...n/fees-outside

and one merchant account, then you sign up for the preferred program with the debit card that you can use to withdraw funds using ATMs.

fees seem to be moderate:
http://www.paypal.com/cgi-bin/webscr...en/ppp-outside

If you then transfer USD 100000 using e.g. your Mileage Plus Visa card to your merchant account, you get the miles, pay the o.7% fee for receiving the funds, and withdraw the money from your merchant account (is there an additional fee ?).
Now you immediately pay it back into the account that will be charged the 100K$ Visa bill!

100K miles for 700 USD, not bad.
Is this feasible, has anyone tried it ?
Of course, if you make the payment with your AA affinity credit card, you can get lifetime Gold and Plat status really quick.

Probably one cannot charge 100K on a Mileage Plus Visa card because of the credit limit but you can use an Amex Centurion card for sure and then you transfer the 100 K MR points to a program of your choice.

Opinions are welcome as usual.
Thank you!