I would like to know if it is possible to get the coordinates from a user clicked point in the current map document - arcpy.mapping.MapDocument("CURRENT")?
There appears to be a solution to this using a Python Add-in over at the ArcGIS Discussion Forums.
There is also a Knowledge Base Technical Article with more concise code. This also mentions that ...
Please note that while I have just tried both I have not been able to get the button I have the code behind to activate so I cannot yet confirm that the code works. I am using ArcGIS 10.1 SP1.
My code for your reference is: