Driveshaft

From all the other issues you have had with your car , I am guessing but I wonder if they welded the end back on the driveshaft correctly. If they are out of phase it will vibrate for sure. The ears that the u-joint goes into must be exactly in line on the shaft. Or the shaft may be bent as well.

There are a few options. You could get one made up in edmonton. Or you could find another used one (or fix yours) and get it cut to length and rebalanced. Does it have the big or the small u-joints? I have a list of the actual length required for your car somewhere that I could dig up. A buddy of mine might be able to the machine/welding work for a small fee. I will ask him but he is off right now cause his dad passed away.