Distribution of Spins, the problem
The Fedora Project has limited disk space, and limited bandwidth, and even if all that were sufficient to distribute all Spins with, there's constraints as to how much data the Fedora Project can distribute to it's mirrors.
From the available Spins in the Kickstart Pool , Spins are proposed to be included in the Release. This is called the Release Selection Process, for which certain constraints apply . Obviously, not all Spins available in the Kickstart Pool are going to be included in the Release.
So, the question becomes, how does the Fedora Project distribute, or aid in distribution, of the other Spins?
Including the Spin on /get-fedora
The Fedora Project could "allow", or "boost" distribution by simply including the Spin on it's "/get-fedora" page(s). By that time, the Spin will have to have been included in the Alpha and Beta release cycles which is the responsibility for the Spin's maintainer(s). Also, the Spin's maintainer(s) are responsible for distributing the Spin (think master seeds, torrent tracker, mirror(s)).
Aiding the distribution
The Fedora Project could also consider allowing the torrent to be tracked using Fedora Infrastructure, but letting the Spin's maintainer(s) be responsible for seeding it (both initially and during the Spin's lifecycle).