This script combines the active layer with all other layers. I created it to make it easier to create with animations using alphaed layers, but it is useful for croloring works, if you have a script to save layer as individual images, too.
The output is an image with all the Layers combined with the last acive one of th old image, so the script can be found in: image->file->create
You have the option to merge the active layer as foreground or to merge it as a background to each of the other layers.
The script is only thested in Gimp Version 2.74 I guess it will not work in Gimp 2.6.
Remember the output order is reversed so you need to go to layer->stack->reverse order
(If I wanted to add this as an option in the script but I get an Image-ID Error Solutions are wlecome)