Mike L,
I don't think we're talking at cross purposes at all. I think what was in question was very clear all along. I mean, asking if you can register a Kindle on an Amazon account is like asking if you can access the Internet from anywhere on the planet. At any rate, I think we've resolved it, and are in agreement over the crucial facts.
On another note, I (and I imagine mgmeuller too) was kinda of hoping you would turn out to be right. Sadly, my DX (and yours and others' too) remains unregistered....
And as things stand, a USB hack maybe the only non-wireless way to get round it.