We've had a longstanding request for this in Fedora too. It'd be awesome if we could coordinate in format and location. See https://lists.fedoraproject.org/pipermail/devel/2015-May/210705.html https://fedorahosted.org/cloud/ticket/93
For Fedora its easy AFAIK. I can just query koji like here: http://koji.fedoraproject.org/koji/packageinfo?packageID=21547
E.g. koji -q latest-build --type=image f24-updates-candidate Fedora-Cloud-Base