Have you looked on ebay? I've seen a few in the past several weeks.
I have, there is currently nothing under "saturna" which doesn't surprise me, but also nothing under "vintage lava lamp" I have seen a few in the past but currently nothing. If you know of one I don't though please send the link.
I realize that his post is close to 2 years old, but are you still looking for a Saturna lava lamp? I believe I may have one.