At my $dailyjob we (kinda unfortunately) went with tons of repositories and libraries upon libraries, and the only sane way for me to make changes across multiple repos is combining them into single build locally. In .NET it's not that complex - remove a Nuget dependency from your project, and add reference to locally checked-out repository and make sure you're using proper tags. It's mundane, happens to be frustrating, but I can make it work.