Ok, a *little* tiny update :)
Got a reply today via email from them! At least someone finally answered my question, but not really very helpful. I have a feeling if I call that number, they're going to tell me the same thing, lol! Here is what they say:
From: DHS WEBMAILDMHSAS
Sent: Friday, August 31, 2012 12:38 PM
To: DHS WEBMAILDPH
Subject: RE: Old hospital records- genealogical inquiry
We do not keep records here. I would suggest you call Mendota Mental Institution at (608) 301-1000
So, short and sweet :) I'll try calling the number next week and see where that gets me. It is a good idea to try the courts too for a court order for comittment, hadn't thought of that, so thanks!