Self-publishing: American English & British English editions

I'm lucky in that I'm publishing mediaeval fantasy where I'd already aimed for a neutral writing style and used an American development editor.

The result is that there's actually very little I need to do to change from British to American standards - a few spellings, a few expressions, not much else.

A modern setting would be something else entirely.
I think this is an interesting idea and shows one of the advantages of indie publishing, i.e. that indies can experiment and try approaches different to those of established traditional publishers. The advances in e-publishing over recent years also make it easier to prepare and publish revised editions of books, and at relatively low cost.