I asked the same question of the FDA on August 2 this year. Here is a response. If anyone knows of such a repository, I'd be interested in some analysis.
From: CDER DRUG SHORTAGES
Sent: Wednesday, August 2, 2017 14:05
To: (Redacted)
Subject: RE: Historical Drug Shortage Data
Good Afternoon,
For past shortage information, the best place to get an archive of past shortages posted on the FDA database is the WayBackMachine which can be found here: http://web.archive.org/web/*/http://www.fda.gov. You type in a url and will get a chart of when the snapshot of that page was taken. Here is the URL you can use for the drug shortage database:
www.fda.gov/drugs/drugsafety/drugshortages/ucm050792.htm