how to only have one custom post type post?

Is it possible to limit a CPT to just one? What I’d like to accomplish is creating a CPT called “Home”. It will manage any and all elements on the home page. I want to program it so when the user clicks on the “Manage Home Page” link they will go straight to the edit post screen. They will skip over the “All Post” screen. Does anyone think this is even possible?

Or maybe someone has an idea to accomplish this goal a completely different?

I would suggest creating a Theme Options page for this purpose.

https://wordpress.stackexchange.com/questions/tagged/theme-options

add_options_page() in Codex.

Or is there anything special in the post edit screen that you want to use that would be hard to get into the Theme Options page?