I'm sorry: there's an "old man" dialect? Really?
Other than that, you could work on dialect from ANY bit of dialogue for the most part and wouldn't actually need anything special.
That being said, most professional theater is copy write protected and not easily accessible online. (Some of it is of course) It's called research. And work.
Lastly, I have to admit, I'm may not clearly understand what you are actually looking for or how you want us to help.
If we're not having fun, then why are we doing it?
These are DISCUSSION boards, not mutual admiration boards. Discussion only occurs when we are willing to hear what others are thinking, regardless of whether it is alignment to our own thoughts.