: Suggestions will be welcome. The theme of Findegil's Insiders' Guide is stuff people don't normally find out about THE LORD OF THE RINGS, or Middle-earth. It's all very extrapolative but is based on obscure passages that I can find.

How about the topic suggested by Alexander below, under the title "Tolkien's Eye," about POV and that all but a few incidents in the LR are ones that were either witnessed by a surviving character or known by some person Frodo could ask. The two of the possible exceptions that he cites are intriguing in themselves.
Another aspect of this is possible "bias" in Tolkien's narratives, as picked up from the alleged sources. There is an essay _Proceedings of the J.R.R. Tolkien Centenary Conference_ by one Alex Lewis entitled "Historical Bias in the Making of _The Silmarillion_" which argues that Tolkien slanted the presentation of the Silm. very subtly to reflect the biases Bilbo would have picked up in Rivendell, so that Elrond's closer kin are portrayed in a better light than his more distant kin, specifically the Feanoreans (who weren't always craven and treacherous).
Have you seen this? I figure you're a better judge of the validity of Lewis'es arguements. Might make for an interesting article, even be applicable to the LR.
Just a suggestion.