I downloaded all of the BRK.A annual shareholder letters, PDF'ed them, and combined them.
I think it could be useful if you want to search through all of the letters at once to see if WB ever wrote about a certain company/topic.
This is an update to the file I made late last year. I added a table of contents, clickable from within the document, and with bookmarks in the side panel as well. In order to view the file properly you will need to either view it in Firefox, or download it as a PDF and view it in Acrobat/Foxit. The Chrome PDF viewer doesn't support the clickable links in the file.
Anyways, here is the file.
Good luck and enjoy