I would like the ability, on a per product basis, to specify what country it is going to be shipped from. In this particular case, if the country specified was not US, then USPS would obviously not return any shipping options. Fedex and UPS would return shipping options only if they ship from the specified country.
This feature would allow for a custom shipping module that could (for example) retrieve rates for Australia Post, if the specified "Ship From" country was Australia, and you would not have to worry about rates from USPS being displayed.
This would probably be better solution than this one:
http://support.shopsite.com/forums/viewtopic.php?f=9&t=7816