I wonder if there is a possibility of adding gocode to an Emacs repo (such as melpa or marmalade)?
Yes, why not? Everything in this repo is licensed under BSD: https://github.com/nsf/gocode/blob/master/LICENSE
Except for one of the emacs scripts, it was licensed under GPL by its author: https://github.com/nsf/gocode/blob/master/emacs/go-autocomplete.el
Oh, and the script for company-mode (which I wrote and I'm using) is public domain: https://github.com/nsf/gocode/blob/master/emacs-company/company-go.el
If GPL isn't a problem for you, then sure, do it. I don't mind. :D