Whelp, think the mystery is solved, at least to my satisfaction. Going off cyclotoine's suggestion that it was a rebadged Peugeot, I searched through some Peugeot catalogs until I found the Yellowstone hybrid bike, which has all the same distinct features, such as internal brazing, same cable routing, fastback style seat clamp, unicrown fork, etc. So, you all were right, and I was wrong but I still think it's more interesting than a Peugeot, even if it's just a Peugeot.
And for anyone else looking at a vintage LOOK mtb, I'm pretty sure they're also resprayed Peugeot frames with Ritchey forks. Take a look here: http://mysite.verizon.net/vzerndgo/id104.html
Could just be the difference between model years. Not uncommon for the same model to have two eyes one year, and only one the next. Same with the adjuster screw.
And another possibility is that LOOK actually designed the frames, and Peugeot took and painted a few.