Pulp Heroes vs Cthulhu Mythos.
I started to work on something like this ages ago and got as far as certain pulp digests and radio serials being
slightly altered factual accounts of missions undertaken by a secret, government-funded, agency. Said pulps and radio shows were used to generate additional funding for said agency and, additionally, provided a great cover for field operations (e.g, if an agent who looked suspiciously like, say... The Shadow were captured in Nazi Germany, he could eaily be dismissed as a random nut). I worked up a brief timeline, as well, but never got much further due to other stuff cropping up.
I still think that it's a valid idea with a lot of potential. I was approaching it from a modern day standpoint of these heroes re-emerging to pass on the their mantles to others for a coming battle with Mythos entities and their followers, but the pulp era of the organization would be rife with potential for adventure, as well (perhaps moreso). I like the idea of pulp heroes being
real, as well as
human (thus susceptible to the rigors of aging, and needing to pass on their mantle to a younger generation).
I think it would, at the least, make a swell mini-setting for THRILLING TALES
[Edit: Incidentally it was a short story penned by Robert R. McCammon that inspired the idea - a story that I believe you may well be familiar with, given your character contribution to Jared Sorensen's
The Code.
Night Calls The Green Falcon.]