I can't personally verify that it's working but I'll take C4E's word for it, that to at least some degree single-layer 360 backups are working.
(V5.1) Single Layer DVD disc support(+/-RW) for both Xbox1 and 360
(V5.0) Single Layer DVD disc support(+/-R) for both Xbox1 and 360
(v5.0) 360 file ISO support (Work in progress. New QWIX tool to come)
Correct me if I'm wrong but when you write a RAW dump or an ISO dump to discs, both discs in the end sould be identical. The support should be there and working, the tools to do it with are a work in progress, and last time I went into the QWIX channel in their IRC server they wouldn't give me a rough estimate even of when the new version is going to be out. Hopefully this will happen soon so I don't have to spend all this money to every game that I've already spent money on to backup. Does anyone know if there are any other tools out there right now that will make ISO backups of 360 games?