I see that you already found the BBC Classic dock and flight codes listings that I did and Ian Bell posted to his website. The easiest thing would be to do the same for v.5 once its ready. In the meantime happy to answer any specific questions you have. I don't intend to do a C64 version, so up to you what variant you come up with.
Hello! Well, if you do publish the Elite-B code, then that should be all I need bar any specific questions when it comes to actually implementing changes; right now I'm still very much in the process of commenting and working out the behaviour of the code. I was hoping I could get source data from you for things like ship models (the C64 uses the same format as the BBC) and the Encyclopedia text as the scrambled text data in Elite is a real PITA, that can always wait until you release your code.
What assembler are you using? I hope you can put the code on GitHub, I'd like to be able to contribute some stuff, like a better manual.