Hello Rob,
Sorry for the late reply - I had to check with our development department on this.
We do have plans to release RU Server for Linux/Mac, but, unfortunately. this will take some time to release. As for the CentOS support - perhaps, it will be available along with the standard Host for Linux as soon as it's released.
Unfortunately, we cannot provide any specific ETA on this yet, but it will be released after the Host for Mac/Linux itself.
Hope that helps.