I finally reopen that. Working at other things, I had some thoughts.
- I noticed that it was in the first design (even in the/a war story).
- Moreover we have know the necessary code to allow such things (Upgrade related code, special filters and/or civ replacements...).
- All previous remarks (mimo, elexis, ...) are still accurate.
So that's mainly a gui issue now. (But there is no urge for doing that, there is even imo prereqs patch to start looking at that).
(edit: the current attached patch is obviously naive, wrong, clumsy, bad...)
