[RickOShay]

I believe when being used to mean "probably" or to show a persons conjecture　でしょう（か） comes at the end of a sentence. I really cannot think of any mid sentence examples off the top of my head. でしょう（か） is also the polite form of だろう（か）

could you show us those few places it wasn't at the end you found?

The verb doesn't come at the end of 彼は明日来るでしょう? I am pretty sure it does..In fact the verb should come at the end of any Japanese sentence. verb +　でしょう・だろう、.. is how I most commonly use the word.

I am kind of not sure exactly what you are not understanding, but I think you might be looking into a little too hard. I see this used like this most often. Ex: これはいいでしょう？ adjective+でしょう。。。in this form　でしょう、 is replacing the verb です、or だ as a more polite, or indirect way of imposing your opinion on the other person. in sentences like 彼は明日来るでしょう？ I believe でしょう is now an adverb and is expressing your supposition about the guy coming tomorrow...and it is more polite than saying 彼は明日来るだろう？