This article in the Washington Post discusses how "a multimillion-dollar treasure trove of 19th- and 20th-century art has been discovered in basements, boiler rooms, closets and hallways in Philadelphia's cash-strapped public schools."
While the chances of DC area art schools having a hidden art trove is slim to none, let me tell you where I think there's a hidden treasure of artwork - not from the 19th century, but nearly all from 20th century (especially WPA period, and 50s and 60's): The storage buildings where the military's art collection (from the various services and mostly from closed bases all over the world) is "stored."
Not the significant and important art collection on display at the Pentagon, but the stored collection of thousands of works of art that a few years ago were stored in a couple of buildings at Andrews Air Force base. As I recall, there was some sort of investigation that discovered that the Department of Defense had little or no accountability or inventory for many of these works.
Sounds bad, but it is understandable. In fact I would submit impossible to have an inventory of artwork commissioned, donated, gifted, etc. to potentially thousands of U.S. military presences all around the globe in the last two hundred years.
As bases close, often things like artwork find their way back to this area, and they are/were stored at Andrews (at least ten years ago they were... not sure if they are still there). Sometimes they find their way to DLA and the various places where the public can buy anything being disposed of by the DoD (there used to be such as site around Fort Belvoir, Virginia).
But in any event, a DoD employee is/was resposible for maintaining accountability for this art collection, and in the mid 90s she was apparently fired/quit in part because a military Inspector General's team discovered that the works were generally unaccounted for and in many cases improperly stored (leaky buildings, rain, moisture, etc.).
All of these issues I am recalling from memory (I read the story initally in one of those air line magazines), but some things stuck in my head: the number of artworks mentioned in the story as being stored at Andrews (in the 100s of thousands) and the fact that there were many WPA pieces in the storage area, as well as possibly up to six unaccounted Norman Rockwell paintings.
Sounds like a good story for an enterprising Washington City Paper or Washington Post reporter to follow up on, uh? Maybe Teresa Wiltz? or Jeffry Cudlin?
I suspect that the accountability problem still exists. In fact I submit that the various services' art curators (each service has an art curator for its own art collection and they all have offices at the Pentagon) do not even have an accurate inventory of the artwork on display at the Pentagon today!
My suspicions were kindled when this story in Art News discussed the fact that US Army curator Renee Klish discussed the fact that four important paintings had been destroyed by the 9/11 attack, but says that eleven other artworks "may have been destroyed."
I am willing to bet that if the Andrews Air Force base artwork storage building still exists, that there are works in there worth hundreds of millions of dollars and maybe still being stored away in improper conditions. I hope I am wrong about the latter.
Update! An alert DCARTNEWS reader also recalls the story I mentioned (published in an air lines magazine in mid 90s) and she even recalled the name of the fired/dismissed/she-quit DoD Art Curator. I have it and will pass it to any enterprising reporters who want to follow up this story - in fact I even have contact info, since I recognized the name as someone still associated with the business of the arts in our area.
I am on travel this week, so the posts will probably come at odd times during the day, so check often!
There's a Catholic school playground joke that goes like this:
The current issue of the 
The long awaited and often-protested against, 
Tomorrow is the long awaited opening of the Ana Mendieta retrospective at the 
