Hi TropicAlex, One of the first times I visited my contact there, I went in armed with info fresh off the web site, and she told me directly not to trust it. This last time, she sent me down the hall to see a "latest" posting on the door of an another office, but this alleged posting was not there. The Director granted a few minutes of conversation (apparently, I know her from the time I worked in Antalaha), during which she told me their machine could not produce visas for greater than five years (to avoid corruption?!?), and that they had reinstated the "droits" de visa to recuperate money that foreigners were unrightfully getting away with.
As for dual (though I like your calling it a "duel") citizenship for an American, I've read both it's possible and the US govt does not allow it. I don't think becoming a citizen here would afford any protections because, as you pointed out, you'll always be considered a Vazaha (i.e., potential source of income) by the locals.