Excellent stuff, guys.

I would second the idea of listing the rule differences for RTWs starting in NA v. say Europe.

Also, if the itinerary begins outside NA, it's possible to purchase one or two additional segments over and above the six you're allowed in NA. I regularly do AONEs ex-CAI and purchase two extra Y segments to cover the shortest routes in the US (eg LAX-SAN) at $150 each. Not cheap, but generally better than buying one-way tickets. The additional segments don't have to be in the same class as the main RTW ticket.