Many years ago I wrote a "Vikings & Dinosaurs" setting for Pyramid magazine, and I think about re-visiting it every now and then. Thanks to Infinite Worlds' banestorm McGuffin, I was able to drop some medieval Norwegians into the South Pacific of a timeline with no K-T extinction, and since it was part of the IW setting you could even have modern-day time travellers drop in and join the party.
PaulDrye
I wish I could remember who pointed it out (it was in the last year or two) where in a review of the original Little Black Books for Traveller, the reviewer noticed something about what Marc Miller had written back then. "Play" in that ur-Traveller included just rolling up characters and making subsectors for one's own entertainment, among other similar things. This was a revelation to me, as personally I don't actually play the "A bunch of players get together and send their characters on adventures" very often. I've always played through creating, but had never thought of it as the same quality of thing as the dominant paradigm.
If play can be encapsulated by something that far away from what people normally think of, it makes the idea of "one true way" that's in turn a subset of tabletop play even more ludicrous -- no pun intended.
If I may (and if not, please delete this), I recently started blogging about the various commercial Cepheus Engine settings I'm developing as well as whatever noodling I engage in for amusement's sake. It might be useful for someone looking to publish their own stuff to see how the sausage is made!
EDIT at Yora's suggestion: The blog is called "Secondary Creations".
Murderous as the Taiping Rebellion was, it would make a great background for the Mythos!