The validation of debt letter DOES work. My sale is on hold at the moment. My situation was so unique I just drafted my own without using a model letter. I had never received an accounting of the arrearages I paid in 2008 to stop a foreclosure then. So, I was essentially asking for an accounting of both the 2008 AND the 2012 NODs. I also have documentation of having requested the 2008 accounting long ago with no response.
Frosted, it surely does seem that some of us have weird paperwork. My loan has had three different account numbers above the table since I have had it. That doesn't include all the numbers I do not know about. The switching of ways to identify the loans appears to have been a perfect way to securitize a loan not once, but multiple times without anyone realizing it. There are now a number of us on various threads here who do not fit the mold of the tidy securitization plan, but have loans which went to some mysterious place. So far, I am not MERS, not Fannie, not Freddie, not in SEC, and the trail grows cold. Those who do the securitization research have a special keyboard called a Bloomberg, an expensive piece of equipment, which allows them to search differently than the layperson can.
As for your recording which was 4 years late, I would check what the laws are in your area. For example, they are usually within 15 days or 30 days, and a recording after that time would void the document. Also, check the names on that late document; it is possible to have been robo-signed. There is another thread here on robo-signing, and several sites to look up the known robosigners.
So far the robosigning doesn't have clout in court, but it serves as a red flag to take note of other issues.
Print off all the documents in the county recording office, create a visual of the beneficiary, the trustee and the servicer ( I did this with different colored pencils) and then just get familiar with all those names and leaps. Sometimes something jumps out at you that way and it is obvious where the trail is not continuous.
Frosted, you have raised a very interesting question; if one wanted to keep a pool of loans in one's own private trust, what better loans than those of teachers......hmmm....