I plan on compiling and running some of the code from the rcarduino blog on the teensy over the next week just to confirm portability but nothing that I do really stretches an UNO never mind a Due or Teensy.
For stretching the hardware you should try DIY Drones, thats one area where the size of the teensy will be a major advantage.
EDIT: The main reason I am interested in the Teensy and Due is for audio where speed and 32 bits will have a big impact. The teensy looks interesting for the DSP instructions which may make software filters a possible addition to Arduino audio projects.
I was going to order one until I got to the last stage just before making the payment and saw that it would cost me a total of £94! I then aborted the order process.
Starting from today different resellers will have theirs online and the shipping cost won't be an issue.
The quote comes directly from UPS so there is not much we can do about it.
we're checking with them because we seem to get different numbers all the time so there is definitely something weird going on
Congratulations on the launch. Its good to see a hardware page, stock in the shop, and availability on a couple of online retailers, and its still only a couple of hours after the launch (which seemed to be at noon, western Europe time).
Also congratulations on the prominent warning about compatibility with 5V shields.
When you have a moment, please remember set the github repository to public, and update the "source code to the Arduino software is hosted by GitHub" link. Currently the link points to the 1.0.1 IDE source.