At Memorial airfield in Chandler, AZ there are quite a few Lodestar/Harpoon's, and a Howard 500 in a boneyard there. From what I understand, an Indian reservation bought the field, and is attempting to get rid of the boneyard portion (so far they are successful...I guess one or two of the different owners of the boneyard abandoned it without telling anyone), so I asked about a few of the aircraft.

The story I heard about the 500 there, which is N130P, is that it was flown in one time, and then the bank repossessed it while there, and it just never left. There have been a few attempts at getting it airworthy again, but as of yet, no one has been successful. There is an attempt being made now to get it airborne and out of there before they decide that it has to be scrapped along with the DC-4's, and -6, and Lodestar's/Harpoon's there, but who knows if it will actually happen.
Here's a photo of it: http://www.airliners.net/photo/Howard-500/1196803/L/

One of the Harpoons there is also a rare bird. It has a pod in the nose for guns, which from what I understand is a rare feature on those aircraft.

I'm not sure how accurate all this information is, but it's what one of the people at Memorial told me when I stopped by there a couple months ago (I used to love going inside those old planes...I have pictures if anyones interested).