Totally. I don't think a black dial with a RG case has ever been produced. It'd been a super nice combination and surely I'd order one in that case. My personal preference would be: black dial w/ white case > silver dail w/ rose case > silver dial w/ white case > silver dial w/ yellow case (of course Breguet numerals a must!).
And yes, you don't need an annual calendar when you have a perpetual.