at a sig level that works, but i believe the question here is about
shipping yum configs for repos that are otherwise run off centos.org (
ie. third party content, and mostly packaging fourth party code )

I think what people are looking for is way to have a ppa like experience and if you want more Centos instance in the cloud it is the way to go.

I would ship a tool to enable repo on the fly and provide users with the needed infrastructure (copr [1] is developed with this in mind and already have some e7 goodies [2] )

The enterprise guys will anyway manage their own repositories (shipping internal tools, java, etc...) and don't have this kind of repository management issue.

For example all our repo are enable through Puppet not rpms.

[1] https://copr.fedoraproject.org/

[2] https://copr.fedoraproject.org/coprs/fulltext/?fulltext=el7

my 2 cents,

--
Thomas