I don't know how Ike is positioning the sales strategy with ambassadors. However, any ambassador with some sales experience and know-how could get an appointment in a big company like Apple.
It's all about finding the right entry point and articulating value. It's possible that some larger companies may want face-to-face meetings, but the relatively small expenditure may get approval from lower to middle management.
However, I would agree that sending emails into Fortune 500s is probably not going to get an ambassador anywhere. It will require researching the account, finding a good entry point, targeting a value statement to that contact, making some phone calls, and building a value proposition.
I believe we probably have ambassadors right here on this board with the experience and ability to do that even at larger companies.