I just wanted to say thank you for such a wonderful script that also happens to be customizable. I have been using popups for years on my galleries on my various websites, and that's very out of date by now, so I decided it was time for an update. i had seen scripts similar to yours being used on other sites, and decided I wanted that. Then when I went looking for a script to use myself, fully expecting that I wouldn't be able to really customize it much, since most of the ones i had seen are always plain white. Then I stumbled across yours in particular, and it was so much nicer than anything I had seen before, and customizable as well! I'm totally in love with this script. right now it's only on my webcomic (launching at the end of November), but I've been so impressed with it it will be going on all my other sites as well.
I haven't done MUCH since I only installed it last night, but i have futzed with the colours, on my webcomics art gallery and character pages.
http://kentauroi.com/art/
http://kentauroi.com/characters/
Nothing fancy, I know. just combined the plain white version with the navigation of the white rounded corners version then tweaked the CSS so it matched my site. I have plans on doing custom navigation buttons, but that will take a while, and I'm happy enough with it as is that it's not a high priority.
My big plans have to do with the map.
http://kentauroi.com/maps/
I plan on taking that image, and making the cities clickable so maps of the individual cities are displayed by by Highslide. I think in this case i will keep the base map in a popup so people can keep it open while reading the comic.