Some notes: since the ghc-Cabal-devel package conflicts with the one in the Fedora repos I built it in a separate copr repo and then built cabal-install separately on top of that in its own repo so cabal-install can be updated without having to touch the system Cabal library (since other Fedora packages are linked to it), but I think some of the newer cabal-install features will not work unless one installs Cabal-1.18.
Let me know if you have any problems or feedback on the packages/repos.