I don't have any concrete examples. The bootcamp grads I've met are all working in web dev with fairly limited skills.
Coming at it another way, many of the programmers I've known who work in areas like embedded, high performance, real time, etc. were self-taught, mostly on the job. By that I mean they had some programming/technical expertise and worked someplace that gave them the opportunity to expand their skills through mentoring and real projects. I'm a self-taught developer and I've learned all of my skills that way. But I didn't start with a bootcamp or web development -- I started 40 years ago on mainframes.
I think it's more a matter of time and exposure. I learned high-end computer graphics and mapping/GIS on the job at an oil exploration company that hired me to do traditional business/database stuff but needed people to learn their other systems. I had to learn all kinds of math and new programming skills but I had patient, experienced mentors and the opportunity to work on real systems. I can't imagine learning all of that on my own, from books and online videos, or at a bootcamp, but everyone has different abilities and background.
tl;dr I don't think going from a web dev bootcamp to a significantly different or more demanding technical domain is impossible, but it will take a long time, a lot of work, and the right environment. A CS degree would provide a better conceptual framework to base new skills on than knowing HTML, CSS, and Javascript, for sure. The bootcamp model and mentality -- zero to $100K in six months -- works for web dev for some people because demand is high and you don't need a lot of high-end skills to build sites from templates or hook APIs up. The companies that hire bootcamp grads generally have experienced developers and a process to bring green people up to speed and let them advance.