Variants - allow taxable / non-taxable status regardless of parent setup

I've got some variants in place that act as handling charges and tax add-ons because there's (currently) no other convenient way to set them up. This means, however, that they end up getting tax added on at checkout, then it has to be manually backed out and re-calculated, and ends up being a minor headache. If we could toggle variants/options as taxable or non-taxable, regardless of what the parent item tax settings might be, it would be great.

Also, I could have sworn that I had submitted this type of request ages ago, but couldn't find it, so apologies if it ends up being a duplicate post