> More than once when faced with crossing an annoying border (TSA, sigh) I'd sell the Macbook at my origin and simply pickup a new one at the destination.

Wow! I've heard of this as a practice reserved for the ultra-paranoid, but never actually seen somebody who does it. What's your threat model? Do you have some reason to believe that the US three-letter-agencies might target you in particular? Are you famous in security circles?