I too have one, a H&H .577. I have stopped looking for a case and decide that I would build one. I bought books on building jewelry boxes and will be drawing up my design from pictures (like in this post). I am slowly collecting all the bits to put in the compartments. I may even try my hand at some tiger hunting scrimshaw on some yellowed imitation ivory to inlet into the lid.

They just don't make pocket pistoles like they used to.