I took the plunge and opened up the innards of one of our existing bathroom scales. After probing a little bit, I concluded that the extra sticky double-sided tape was only present under the 4 load sensor corners. That made it a straightforward matter to  remove a big chunk of plastic with a hacksaw and side cutters.

Here's what it looks like after a barbarian hacked away at things. The free-floating red and black wires were the power leads from the battery compartment. I'll be discarding the display and controller board.

Here's a close-up of the two sides of the controller board. The cut off "BZ" leads are from the small piezo buzzer (the scale beeped when its weight measurement stabilized). The manufacturer blobbed over whatever chip they were using, which seems like a pointless exercise in something to commonly understood already.