I view a bunch of comic strips when I sign on every morning, and I think the Bloom County from April 15, 1988 qualifies as a slide rule sighting (the Seattle Times is rerunning old Bloom County strips, and they're currently into the strips from that April)
It shows Steve Dallas asking candidate Opus to speak at a fund-raiser for a troubled industry, "Slide Rule Aid"
If this has already been noticed, I apologize.
Phil Stanley
Worcester MA