I left off "as cheap" because you didn't say it, but it's a huge part of the puzzle that you deliberately ignored, too. But I'm really interested in seeing these "furniture panels" that you're recommending.
One example where IKEA hacking wouldn't have helped: I needed a thin (20cm) and short (80cm) locker for the bathroom. Ikea had nothing close to this -- at least 30cm thick and 1.5m tall. So, I searched Leroy Merlin catalogue fr the most suitable door facades (they weigh twice less than particle boards of the same size) -- and designed the locker around them. We've been using it for 2.5 years.
Not sure what IKEA offers here, but I ended up with putting "hanging" cabinets on the floor in my bathroom because thy are thinner and shorter than what is available as actual standing cabinets.
It's completely functional and not ugly. Again, you can choose real wood or some of those composites. Also maybe changing screw system (the original setup is like the one showed in TFA) you could make it nicer. I bet there are tons of designs like that out there.