I've been a long time fan of just hacking stuff to make it work for each individual site because of tight deadlines, but now I decided I wanted to make a general Ubercart theming module which tweaks and styles the Ubercart checkout that I can use on my sites and at one time maybe even put on drupal.org.
It's been great so far, but I'm now at the checkout complete page and I can't find a single decent way to theme or alter the output on that page.
It seems to me you didn't add a theme function here because of the ability to set an alternate checkout completion page in the ubercart settings. Setting a different checkout completion page is not really an option for me because a lot of modules depend on the default one.
Is there some way of theming/altering the output of that page that I'm missing?
Btw, I'm using the latest recommended version of Ubercart 2 for Drupal 6.