iiuc, but don't quote me, the CRD client & host are open source, and you could build your own. i suspect you'd have to provide your own API keys. you wouldn't be able to customize the CRD host that runs on the Chromebook, but you would be able to connect to it with a custom CRD client from a diff machine.
but i'm by no means an expert on this, and i could be wildly wrong -- CRD isn't part of the CrOS project. i don't know that CRD has any public groups where you could ask questions though.
maybe Lambros would know more.
-mike