I think the unity watermark itself is also only a guitexture, within a nice little component that helps to get those effects.
I think its scripts are even included somewhere because I recently had it in one of the projects I’ve here on the disk. But don’t ask me in which … I’ve like 13 projects or alike, two own prototypes, an ongoing iphone game in development and the other are from my work for a company, covering different distinct 3rd party library integration and alike and I think there is also somewhere a project which I started when I first got Unity3D which has all kind of packages included from the resource section …