It's in oa_ctf4ish as well, IICR. People spotted it in 0.8.5. There's also an Invulnerability force field holdable, but isn't modelled.
In the SVN, (what will be available in the next big version of OA) there're several maps which include it.
Can't wait for that next version!
WTF it's in ctf4ish? I've never seen it there. Well, that would be rather fun to use...