Well, what do you know, this baby works, and I'm typing on it right now.
I used the trick with the wire and the tape, only I didn't use clear adhesive tape, but more like white semi-transparent paper tape. I would take photos of the process, but my phone can't take such close macro photos. The biggest trick is to scrub the plastic on top of the ribbon very, very lightly with something sharp (I used a scalpel). When I say lightly, it's almost in a way that you can't feel it. Just put blade on top, don't press it, because weight of the blade itself is enough, and scrape up and down a bit.
It's been a bumpy road, and the keyboard ended up my little monster:
1. SDL port broke, so I had to desolder it, and solder another one from another controller. SDL connector on the cable also got damaged, so the whole setup is kind of semi-detachable

2. The membrane ribbon got cut, as outlined above
3. I also did a screw mod. Since this was my first mod, I was overly ambitious, and tried to follow phosphorglow's recommendation to "spread" the screw holes. It didn't help that I didn't hold a drill in a couple of years, so the end product doesn't look pretty, to say the least.
Buy hey, it works! And it isn't going anywhere
I finally have time now to turn to my XT. And there is a rubber-dome model M that I got last week, that is about to be dissected for greater good
