Yes it's been done, but not for LOGIC!
I was just kicking the walls yesterday about this -- DAW's have the latest greatest cutting edge computer technology, but they still lack many of the basic functions studio cats took for granted 30 years ago!
Sure, you can "build your own" talk back kludge in the Logic environment. Is it easy? No. Is it simple? No. Is it simple to import into other projects done before you built the kludgy thang? No.
This is a basic necessary feature, and it's very telling that the wizards at Apple/Logic are so clueless about why anyone would even need such a feature. It's stuff like this (and about a dozen other 'basics') that will keep me referring to it as Logic SemiPro for the foreseeable future.
Now MAKE THAT PLUGIN! I'll BUY IT!