We'll save the flattery for our spouses, and start by examining some key areas of interest that you might want to be able to change on a UAG implementation. Typically, the end user interface is comprised of the following:
There is also the Web Monitor, but it is typically only used by the administrator, so we won't delve into that. The UAG management console itself and the SSL-VPN /SSTP client-component user interface are also visual, but they are compiled code, so there's not much that can be done there.
The elements of these pages that you might want to adjust are the graphics, layout, and text strings. Altering a piece of HTML or editing a GIF in Photoshop to make it look different may sound trivial, but there's actually more to it than that, and the supportability of your changes...