Is it easier to buy a US mains lead for your gadgets when travelling to America, or to carry around a US travel adaptor?

I'm off to New York in a few weeks and I'm thinking about the best way to power my tech. Well, I'm thinking about that and possibly battling my arch nemesis underneath Madison Square Garden. I'd hate to miss our appointment with destiny because my phone ran flat.

I'll be taking my iPhone 4 (perhaps with an AT&T SIM) and my new 11.6-inch HP notebook on the trip. As luck would have it, my first iPhone was shipped over from the US so I have a shiny US two-pronged NEMA-1 iPhone adaptor tucked away in the cupboard. When I bought the HP notebook on the weekend I was please to see that the power supply and the C5/C6 "cloverleaf" AC mains lead are separate, so in theory I could buy a separate two-pronged NEMA-1 cloverleaf AC cable without buying another power supply. I'm concerned a chunky travel adaptor might cover two sockets in my hotel room. A US mains lead would be much more elegant.

Great plan, except for the fact they just don't seem to sell these US cables in Australia. I thought I'd have no trouble finding something like this in Radio Parts or Jaycar, but no luck. I guess there's not enough demand to make it worth stocking them when you can just buy a travel adaptor. You can obviously buy such a cable online from the US, but it might not arrive before I leave.

It seemed like such as elegant solution, but it looks like I'll end up lugging around a travel adaptor after all. I'd hate to miss my date with the Kurgan.