Thanks to all for the thoughtful feedback on this. Here's my take based on the comments and what I have found in my research:
I very much like the idea of having a servicer handle the transaction. It seems that they are uniquely qualified to do so due to the fact that they are dealing with notes and funds escrow on a daily basis. I mentioned the FCI exchange example earlier, They provide a nice escrow and closing process for transactions between parties for their note exchange.
Title companies may not be the best choice because they are pre-wired for real-estate transactions and perform these functions as a way to sell title insurance. One title company I am talking with is telling me that they can provide escrow services in certain states, but not others due to limitations on where they can receive and disburse funds. In other words, they can only help in states where they are already set up. In addition, I would have to train them on the process.
Attorneys are always an option. I see this approach as more suited to purchase and sale of larger note pools.
Handling the transaction directly with the buyer still works. After all, that's how most note transactions are done, and I will likely offer this as a lower cost option, along with an escrowed closing for those who want it that way.