As reported on Language Log, I recently e-mailed Geoff Pullum asking his opinion about whether slash and cum would qualify as coordinators. He replied saying that he thought they would. This exchange was sparked by a discussion on English Wiktionary. There, the ever vigilant DCDuring suggested that cum seemed more like a conjunction than a preposition and Ruakh replied that he took it to be like slash, which he considers a clear conjunction. The consensus seems to be that, yes, both words are coordinators.
The earliest instance I can find of coordinator slash is from a column in the September 28th, 1992 issue of Time magazine called "Short Takes":
Meet urban planner Campbell Scott (" a realist slash dreamer "), Greenpeacenik Kyra Sedgwick (" This whole decade is going to have to be about cleaning up "), maitre d' Jim True (" I live my life like a French movie ").The next oldest I can find is from the script for the 1999 movie Mumford:
No, what I've been working on, what the world really needs and no one has been able to create a virtually life-like, humanoid, gender-specific, anatomically functional... sexual surrogate slash companion.I particularly like Dear God slash Allah slash Buddha slash Zeus - I'm a big fan of covering all your bases from the 2009 short story, “The Perfect Gift,” by Steven Frank.
I haven't been able to find any examples of slash coordinating clauses, though the contrived example from commenter Luis at LL seems fine to me: This is the man that I work with slash compete against.
When it comes to cum, there's certainly less syntactic variation; it seems to be mainly limited to coordinating two NPs, but I was able to find the following example from 1991 which fortuitously exhibits not only multiple coordination, but also coordinated AdjPs.
The religious cum political cum economic nature of these agrarian rituals of early leaders, including the emperors...This was published in 1991 in Ethnology Vol. 30 Issue 3, p199 in an article entitled "The emperor of Japan as deity (kami)" by Emiko Ohnuki-Tierney.
As far as I can tell, no dictionary lists slash as a coordinator, but Merriam-Webster's does list cum as a conjunction.
[Update: The American Heritage Dictionary does indeed list slash as a conjunction. So, I guess there's no major discovery here. What a letdown!]