Cheers misulicus ..
I've just tried this on a basic test site and it is working - except that it doesn't show sale products with variants? So I'm seeing simple sale items, but not sale items that have variants..? I've tried POST and PAGE and both seam to act the same.
I'm trying this on two test sites; both fully up to date, one works and one doesn't; the broken one just defaults to showing the shortcode as if it was [productspage]. It's not the theme's fault. And this is the same reason why it doesn't work on the live shop site which led me to post in the first place. No idea what's goin on there...
EDIT: Something to do with this message I've not seen before: "Combination of product variants is not available" ..