There's steptalk which is effectively a smalltalk environment embedded inside of the Objc runtime. See also the Etoile project here: http://etoileos.com/news/archive/2006/05/28/2222/

I was going to bring up Etoile; I assume it's dead, since there doesn't seem to been any activity for a few years?

At least in the blog/news areas sure. I wouldn't doubt if there's been development on the IRC channels and the mailing lists, though.

I does seem like they were having a bit of an identity crisis around the time steptalk was put together, though.

I am still waiting for a properly packaged swift 3 for debian. Of course I could add the swift from apple as ubuntu deb pkg. but still we will get gnustep swift bindings some day...