I am looking for a way to embed an .exe into a frame.  (MDI)
I am not sure how this can be done.
I am using wxpython 2.9 and there is nothing online about this (until now).
Embedding one GUI application inside another is not a simple thing.  Applications are written to provide their own main frame, for example.  You could try to position Notepad to a particular place on the screen instead.
If you're really talking about Notepad, then you have a different course of action.  Notepad is nothing more than a text control with some code to save and load the contents to a file.
Embed .exe in wxpython