An incomplete set of layer styles for The GIMP, including:
To add or update a layer style, simply select the layer style's parent layer - the layer the style will or already belongs to - and call the action. This also works from any of the other layer style layers the parent layer has. The scripts will automaticaly find the correct parent layer and/or layer style layer to update.
To be able to run these scripts, you'll first need to install these two scripts, which function as library routines for the layer style scripts:
i don't mean that you should think about trying to implement linked layers withing scheme, but withing GIMP, as for the GIMP design philosophy, it tends to be outline ideas with scripts and write plug-ins or program features once the methods have been explored, go to the GIMP developers and show them what you've done.