Our allies haven't exactly proven themselves on the up & up with us.
http://blog.washingtonpost.com/spy-t...g_us_musl.html
But you have to ask about motivation. I can see maybe Israel, hypothetically, getting their hands on complete tech info for the F-22 and, not having a need to build a stealth fighter themselves, might sell it. But with the vast amounts of cash nations throw at each other, the price tag doesn't seem worth risking the loss of the US as an ally. It's one thing to steal plans for spy cameras & drones to use themselves. It's another to jeopardize US air supremacy by selling stealth tech to a rival super power.