> Could an independent group do the same with the latest RHEL sources?
Yes. But there would be an up-front investment in effort and a slow start, as there was with CentOS itself. The people who started up CentOS and maintained it pre-RedHat will mostly be off doing other things (possibly within RedHat) so that particular source of experience is not likely to be available at all. You'd need to find enough people who are the right combination of interested enough, capable enough on the technical side, have access to enough hosting resource for it to be practical as a public project, and willing to do it for free (unless you can attract some sponsorship or other funding).
Edit: as others said in replies while I was typing the above: it looks like a group has already started working on this, so you might be in luck.
Yes. But there would be an up-front investment in effort and a slow start, as there was with CentOS itself. The people who started up CentOS and maintained it pre-RedHat will mostly be off doing other things (possibly within RedHat) so that particular source of experience is not likely to be available at all. You'd need to find enough people who are the right combination of interested enough, capable enough on the technical side, have access to enough hosting resource for it to be practical as a public project, and willing to do it for free (unless you can attract some sponsorship or other funding).
Edit: as others said in replies while I was typing the above: it looks like a group has already started working on this, so you might be in luck.