QNX, the real-time message passing operating system now owned by Blackberry, does all "console" handling in user space. They've done that for years. That's because, in the embedded world, you can't assume the target machine has a console, or even a serial port.
When you build a QNX boot image for an embedded system, you can add any programs you want to be available as soon as the system boots. All device drivers are in user space, so that's how the initial set of drivers gets loaded. You can also load applications that way. Having a file system is optional. If necessary, all software can be in a ROM. This allows scaling down to small embedded devices.
A serial console program is available, and is loaded into most systems that have a serial port. There are other options for systems that don't have a serial port, like connecting it to a network.
There's also a system logger. It's common to have the system logger log to some network destination elsewhere, so problems out at Pumping Station 42 are reported to the control center far away.
Linux has tried to emulate this architecture. More drivers are in user space. But in Linux that was an afterthought, and it shows.