Drupal 7.0 was officially released on Jan 5, 2011, yet there is still no Ubuntu package available. There is a Debian package available for Sid, but attempts to incorporate it into a TurnKey LAMP appliance proved problematic. I can understand concerns about relying on upstream developers for support, but in this case the availabilty of Drupal 7's built-in updates and Drush's site-install, provide the ability to obtain updates directly from the source.
A new strategy of installing Drush first using git, and then using the power of Drush to download, install, and configure the Drupal site has proven effective. A TKLPatch to add Drupal 7 to the TurnKey LAMP appliance is now available in the Development Wiki, turnkey-drupal7-11.x-lucid-x86-patch-beta1 and also on GitHub.
Moved the remainder of the original post to the Development Wiki where it probably should have been all along.