ted, i think you're right about what will kill you. characters in a gritty, realistic flick will have the right accent. that's why you pay A-list actors millions of dollars and hire voice coaches. but, trust me, few would recognize the difference between a georgian accent and north carolina. even if you're from those two places doesn't mean you know what the other is 'supposed' to sound like. i think most of us could basically care less about linguistics unless it's obviously askew. obviously, something like 'mississippi burning' has to have the right accent, but who among us bitches about a russian accent? no one. i've never heard anyone ever say, 'well, that's just wrong! that character should have a siberian accent!'
people just don't have enough knowledge about other regions on average, nor the ear, to tell the difference. if you say 'georgian accent,' few people will know what that means.