Although I've never owned one and they seem a bit pricey and hard to find, those Godin Multiukes look to be as solid as can be. Body is carved from a single block of wood and the neck bolts on. They are very heavy, and would be my first choice of instruments for fighting off muggers or wild dogs...
Otherwise, I'd agree with the Pono consensus...
I’ve owned a Pono and currently own a Godin multiuke. Yes to both being built solid. The godin does feel amazing in the hand
and has a surprising amount of acoustic volume and it sounds great pugged in. As others have noted - the heavier a solid wood uke is built, the less volume/tone it tends to have.
If you’re looking for durable without the loss of tone I’d strongly consider the Blackbird ekoa ukes (Clara and Faralon). Amazing tone and pretty stout, although not in the same league as a waterman or the Klos carbon fiber ukes for durability.
and a side note because I’m nerdy - banjos run the opposite direction from ukes and guitars - the more structure you get (I.e. heavier) the tone improves and the value may be higher. There are exceptions of course, but in general the high end banjos are pretty hefty.