I was aware of these, it's kinda what I meant by "None of these were really Java Machines". They were just shitty sparc machines that had Java OS in flash. It didn't have some kind of Java co-processor and still relied on a JVM. Java OS was pretty neat but I wouldn't really consider it a "Java OS" since it was basically just a microkernel that bootstrapped a JVM from what I've read. An actual Java machine IMO would have to at least have some kind of Java co-processor and not rely on a software based JVM

Sun also tried, and failed, to bring to market, a microprocessor architecture for running Java on metal - https://en.wikipedia.org/wiki/MAJC