While looking a bit at the Kindle, I found a map showing the 3G network coverage.
Out of curiosity, I had a look at what the coverage looked like in Essen (where I sometimes work) and Hamburg (where I live). Then out of curiosity, I had a look at Denmark - since the UMTS stick I had bought there only got an EDGE signal in our holiday home (2G), not UMTS/HSPA/3G.
At lower zoom levels, it seemed as if Amazon's Danish roaming partner (whoever that is) might cover the place: coverage was spotty in general in north-west Jutland, but there was a dark purple band along the southern shore of the Limfjord and, zooming in, that dark purple even reached up the peninsula where we had stayed, a bit north or Lemvig itself.
But zooming in further showed me something extremely ironic (in an Alanis Morissette way):
The holiday home park was along Vinkelhagevej, a bit to the right of the centre of the image.
Guess at which point along Vinkelhagevej our holiday home was. Go on, just guess.
Juuuust outside the dark purple bit. Feh.
(FWIW, the UMTS stick I had was TDC. I don't know which company that graph is for. But still.)