747,
I'll agree with you that SJO definately isn't YYZ with respect to traffic volume. But, you can get almost any US airline out of there. (Delta to ATL, AA to MIA, UAL -through flight via Guatamala City- from ORD or LAX). That doesn't include any of the Latin American airlines (TACA, COPA -which I have flown and love- Mexicana, etc...). Anyways, it's not just narrow-bodies headed down there. CAL flies 757's out of IAH (okay, not a widebody like yours...
but not necessarily a narrowbody.)
Anyways, I just recommend people look at Costa Rica as a nice place. Just my opinion...