You might look into what's called 'small caps'. They're capitol letters, but no larger than regular ones and not thicker or anything, so, a lot less intrusive. I understand somebody (Brandon Sanderson maybe?) used them to pretty good effect in a story or two.
Hᴇʀᴇ's ᴀ sᴀᴍᴘʟᴇ, ɢᴇɴᴇʀᴀᴛᴇᴅ ʙʏ ᴛʜᴇ YᴀʏTᴇxᴛ ɢᴇɴᴇʀᴀᴛᴏʀ. I think it's less conspicuous than italics or bolding, maybe less than a font change? Type in whatever text you want transformed into smallcaps and then click the Copy button. Not sure that would work in a book, but I'm sure you can get sᴍᴀʟʟᴄᴀᴘs in somehow (maybe).
Yeah, me too, like I said above. This is for those who persist in their stubborn ways. We can still help them, even if we wouldn't do it that way in our own work.