From Araelium Group:
DMG Canvas builds disk images from template documents that you create. Simply design your disk image's appearance using the graphical editor and click Build. Each time you release a new version of your disk image, simply click Build again and DMG Canvas will pull together all of the latest versions of your files. DMG Canvas also allows you to specify the license agreements displayed when the disk image is mounted. With DMG Canvas, you customize every aspect of your disk image.