The result of the last couple of days so far is the ground work for a Neovim specific port of Spacemacs, located here https://github.com/Tehnix/spaceneovim. The major difference between that and the existing spacevim is that the layers are separated out from the core, and can be updated via an editor command (calling git pull). It makes it a lot nicer to add new layers later on (oh, and of course also the fact that I've dropped any though of vim support).
Contributions or feedback are more than welcome! :) The easiest way, if you want, is probably to contribute a layer, or expand on an existing one at https://github.com/Tehnix/spaceneovim-layers. One of the goals is to match Spacemacs more-or-less, so switching isn't annoying (hence why buffer/filetype specific keybindings are behind a '+major-mode-cmd').