So just as a disclaimer I have no idea how possible this would be, although I can guess it wouldn't be very easy
The basic idea is basically PISS but it replaces text right before it gets displayed by swapping the string it was going to use with a new one. Either that or it does the replacing when it reads the text from the msg file. This would be pretty useful for some simple text based mods I've had in the back of my mind, and would likely bypass an annoying bug with the BF decompiler that incorrectly decompiles some addresses
This is something I'd like to make at some point, but right now I'd just like some input since I'm only 1/4 of the way through my modding break