We also experienced a $5000 NW Worldperks Visa credit card charge limit from a motorcycle dealer where we wanted to charge over $10,000, i.e., the entire cost of the bike and had the credit to cover it on the card. I don't know if the restriction comes from the dealer or from Worldperks and other similar frequent flyer miles credit cards.

What I'd LOVE to charge or "launder" every month without cash advance fees on miles credit cards would be our San Francisco Bay area mortgage payments! We'd be flying first class at will if those enormous charges could generate miles. :-)