Any online travel agency??? I would think that they would have no trouble issuing you an e-ticket on a major airline for a Sunday departure, provided you pay with a credit card of course.
In my past experience, I've been able to buy short-notice (next day, domestic) tickets at Expedia with no problems. I'm not aware of different rules for int'l. In my case, Expedia always matched the lowest fare I could find elsewhere (except, of course, where a NetsAAver or Web Special 'L' fare was in play). But definitely check both Travelocity and Expedia, as well as your target airline's own site, at a minimum.
Finally - if you are dead-set on AA, PCLN is definitely *not* the place to go. They will put you on any airline they feel like, and the tickets are nonrefundable. I think I'd rather take a Greyhound to the east coast and a slow-boat from there than use Priceline.
[This message has been edited by rmccamy (edited 03-29-2001).]