Kidney Cloning

Organ donation is an interesting thing. You can donate some things while you're still alive. A large portion of your liver, which will grow back. One of your two kidneys. One of your two lungs. (Those don't typically grow back.) Other things, you can donate when you die. Your heart. Other things, you'll probably want to wait until your death to donate, like your skin or your corneas.
I was reading earlier this week about how scientists have rebuilt lungs to improve compatibility. Essentially, your own diseased lung is rebuilt from scratch using your own stem cells, then reimplanted. They reported that this will save hundreds of lives every year, because hundreds die while waiting on donor lungs. You can also use a donor who would otherwise be incompatible, which saves even more lives.
And I was thinking, you know what other organ could benefit from this? Kidneys. Millions worldwide depend on dialysis, because their kidneys have totally failed. There's a limited number of machines, and we can't seem to build more fast enough. But if we rebuilt the patient's own kidneys, they would no longer need dialysis. It would be merely a stopgap measure to get them through the failed period, which is no longer "the rest of your short life." In fact, the more organs we could apply this to, the better the organ donation works out. Incompatibility would cease to exist, making every donated organ more useful.
But the best aspect of all was suggested by a reader of the original article who called himself "dancupid." He suggests using 3d printing techniques to lay out an artificial extracellular matrix. If that could be done, then we never need organ donation again. Each person could have an organ bank of 5 or so of their own organs, grown from a printed extracellular matrix and their own stem cells, and kept alive in life support machines. If I get stabbed in the kidneys, I can have my loved ones take a kidney from my organ bank to the hospital, where they implant it. The stabbed one can be donated to someone who couldn't afford the printed organs (and will have its cells replaced with their own), and when I get home, I print a new one in case this happens again. If my lungs should develop cancer from all the air pollution, I have a printed replacement ready to go. If my heart should give out, as happened to many of my ancestors, I have spares. In all cases, I'd cheerfully donate the old one.
....dear God, we'd be nearly immortal. We'd last as long as our brains. (You could print a new one, I suppose, but would it still be you?)