Well if you ever get your answer, please post it or DM me.
The only other things that came to mind from that time period that I know of that kinda fit your description are The Boards, but they didn't release a 7" in their time, there was just a posthumous CD collection.
There was the Atheists, but I'm pretty sure they just released a demo or had a couple comp tracks - I've never come across either, just been told about them, and I believe they were described to me as being more DEVO-esque.
Bad Yodellers were post-Massacre Guys, but didn't have vinyl out until the early-90's (and it sucks), but their mid-80's demo is killer and worthy of a vinyl reissue - probably too late for what you're looking for.
L.D.S. had a 7" and an LP and were kind of a mid-80's death rock / hardcore hybrid.
The name Excel doesn't really ring any bells.