
This lead me to realise that in Inkscape, layers are simply another group so why not just clone a whole layer?
unfortunately, you cannot select layers in that way in Inkscape without going to the XML editor... This bit is a bit technical! simply create all the clones on another layer, then edit their xlink attribute to refraction the id of the layer you want to clone, then lock the layer containing the copies to prevent them being moved...
I then thought, why not make a Kaleidoscope with all this knowledge... or at least a simple mirror image thing! so check out:
http://openclipart.org/people/tom/tom_4 ... mmetry.svg
for one you can download and use without doing the xml editing stuff!