I ended up buying the Samsung 3 recommeded in the article that Littleman linked.
Since the article, the Samsung 3 has gotten full Crostini support. That means you click on toggle in the settings, wait for a 300MB download (first use only) and it launches a full Linux container.
I haven't looked into it, but apparently it's a standard LXC container, so in theory you could build an entire server on your Chromebook, export it, import it to any machine running LXD and it should just run. I've always been stymied every time I've tried to get Docker to work, so I don't see myself doing that anytime soon.
Plus it's half the price of the ruggedized machine I was initially looking at. So for a machine that is meant to be a burner, that's a plus.
My impressions... I actually love it. I have a few programs that I use on my Windows machine that I can't run on a Chromebook (Photoshop, Beyond Compare, a couple others, but not many).
And onboard storage is limited. However, it is currently $89 for a 400GB microSD card and my main computer only has 460MB on the data partition and that includes 75GB of materials from my old job and 200GB of photos, many quite old and many existing in multiple copies.
Beyond that, I actually love it. I could see my next machine being a more powerful Chromebook. Apple fans are always saying that it just "feel" better than a Windows machine, but they pay an exhorbitant premium for that feel in my opinion. With the Chromebook, I sort of have that sense of pleasure in working on it, but instead of paying 3X what I would pay for an equivalent Windows machine, it's a $172 burner that I took to the desert and didn't worry about at all.
My one disappointment is that the machine that I was originally looking at when I started this thread had, according to spec and reviews, over 10 hr battery life. This machine only has about 6-7 hrs of battery life. I would gladly "pay" an extra 100gms for an extra couple of hours. But I suppose shoppers like me are looking at price and weight as main criteria, so it's like the airlines adding legroom - everyone says they want it, but nobody makes buying decisions based on it.