I am in Aussie and have a Kindle, i am able to get a pretty good variety of books , a few geographical restrictions get in the way at times.
i don't know about the availability of kids books, but i doubt you would have any problems.
I have the 3G/wireless kindle and hubby just has the wireless which is sufficient.
We love our kindles, but we haven't tried anything else so have nothing to compare them with, and you are right Kindles are not available in Aussie, well they are actually there are ebay sellers listing brand new ones for 100.00 more than amazons price.
We got ours through Amazon, with no hassles, i think delivery to Tassie was about 30.00.
Good luck with your decision