Ways to Get Stunning Fist?

[Pezzo]

It's obviously giving the monk the bonus feat feature of a fighter. But RAW could technically go either way even if the intent behind it is 100% unambiguous.

It's improving the monk's class feature, expanding the list of feats that can be selected. If it was replacing it, it would say so.

True, but we're gonna bust out Martial Monk, we might as well just take an [Epic] feat or something.

Epic fighter bonus feats is an extra list of feats available to epic fighters, fighter bonus feats are feats that state they are fighter bonus feats in their description, epic fighter bonus feats don't have that.

I doubt this will be helpful, but punpun or an illithid savant can gain the monk's bonus feat class feature.