Barry Malzberg: Push Your Themes to the Limit

So I've been thinking about those historical pastiches lately -- you know, like Nicholas Meyer's The Seven Percent Solution, Jack the Ripper against Sherlock Holmes and Sigmund Freud -- and I thought, wouldn't it be cool to push this as far as it can go, and have JTR & Sherlock & Freud, and Dickinson, and Lee Harvey Oswald, Oedipa Maas, and Jesus and Emma Goldman and Frankenstein's monster and Mark Twain and Jim (Huck's Jim) and Roderick Usher, and Hawthorne (who needs to make a kind of low-key, mournful pass at someone) and Boo Radley, Prospero, Elizabeth II, William Shatner, Teddy Roosevelt, and Nat Turner? And Ted Turner, and everyone else who might be interesting?
Obviously the plot will have to have somebody murdered in such a way that the entire space-time continuum, whatever that is, is in peril. Suggestions welcome.