If only Conrad Veidt hadn't died in 1943. I suppose he might have been a bit old for Roy anyway.

Deckard when he comes supposedly calling from "the Confidential Committee on Moral Abuses."

I agree that Bogart wouldn't work as Deckard, but I'm convinced that scene was inspired by the one in The Big Sleep where Marlowe cases the suspicious bookstore by posing as a nerdy/possibly gay bibliophile.