I tend to share your thinking on this, although at least one knowledgeable online-imaginary-friend vigorously disagrees with me.
I have looked but failed to find a VM image or even images of installable media to build one online. If you know of any, I would like to know -- and if you don't know of any, but have the skills, I think you could do a big service to the OS research community by making and sharing either install media or a VM or both.
It was developed by the same core team that created Plan 9, and Limbo is the evolution of Alef, that Rob Pike wasn't happy to have to drop for Plan 9 3rd edition.
> Alef appeared in the first and second editions of Plan 9, but was abandoned during development of the third edition.[1][2] Rob Pike later explained Alef's demise by pointing to its lack of automatic memory management, despite Pike's and other people's urging Winterbottom to add garbage collection to the language;[3]...
> The Limbo programming language can be considered a direct successor of Alef and is the most commonly used language in the Inferno operating system.
> Inferno was based on the experience gained with Plan 9 from Bell Labs, and the further research of Bell Labs into operating systems, languages, on-the-fly compilers, graphics, security, networking and portability.
For some strange reason many stop at the middle station, instead of going all the way to the end.
One of my favorite features of plan9 is how it handles the bin directory.
For one, you can have sub-directories inside the bin directory. This lends to a nice hierarchy of commands and encourages writing small single purpose commands instead of large monolith commands. An example of this is the `ip/ping` command.
Another feature uses the union file system which prevents me from having to mess with $PATH locating commands.
http://9front.org/
https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs