A few options if you're incapable of impressing people by phone...
Get to know a couple advertisers at networks you want to work with. You could even consider going direct for a little while if they offer that option. Once they know you a little better and they're willing to vouch for you, offer them as a reference to one of the networks they work with.
Not saying it's particularly honest, but I've heard of more than a few people who have gotten US forwarding addresses or US-based partners who make the approval process much easier.
You can also go the "social validation" route and build up a social media presence, get to know a few AMs through Twitter and stuff, etc. Once they know you and they know how you operate, it should be considerably easer.
Save your cash and go to something like Affiliate Summit/ad:tech/etc. It's easier to get approved when they've met you in person.