I lowballed the ebay seller and they accepted my offer for this:
its from a nissan stanza with a digital rpm part of the cluster I'm guessing? I've been searching for 30 minutes and haven't been able to find one lit up. It shares the ka24e with my '90 so maybe it won't be too hard to wire up, especially if I can find a plug
edit: FAIL. the shit is a piece of plastic. apparently some just didn't come with tachometers. oh well.