We did that a while ago: we ran into some issues loading the kernel into the Qube3 rom memory as it turned out to small to handle the SME delivered kernel... same issue we had with trying to install anything else (like Redhat 7.3).
I don't remember where I left it, but there is a site (somewhere...) which provided an insight into tweaking RedHat to install on a Qube. We did that, so I would say it is possible.. I am not sure if it is worth all the trouble...