Question: I need to extract the document location of a published web service. Is there any way this can be accomplished in python?
I know where the maps are sitting on the server, and i know the name of the service and what mxd file they're based on, but i need to accomplish this programatically.

Answer: 
Unfortunately no. As Alex said, there is no real link between the original published mxd and the service (although there was in previous versions). You can however find a copy of the published mxd on your server in your ArcGIS Server directory at %arcgisserver root%\directories\arcgissystem\arcgisinput\%service folder name%\%service name%.MapServer\extracted\v101
<https://developers.arcgis.com/rest/enterprise-administration/server/servicemanifest.htm>

You're looking for "resources" --> "onPremisePath" which should give you a record of the original MXD file path.