AFAIK, there is currently no license having a slot reserved for a backlink URL that is recognized by the FSF or OSI.
It is not hard to create such a license. Adding a slot for the backlink URL to the ISC License and altering the permission statement as follows will do it.
Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice, URL and this permission notice appear in all copies.
The ISC License is permissive, and recognized by both the FSF and the OSI. Your custom license will not have this recognition, and license proliferation should not be encouraged, so I do not think you should go on to create this custom license - but it is certainly possible to do so.
However, in free software project I generally find contact information helpful. This goes both for project email address and backlinks that points to project members or master repo. While link rot and email becoming a black hole is not unheard of, I still prefer to have access to contact information than not. This allows me to contact the maintainers to inquire about the status of the project, and to make pull requests if I've fixed a bug or added a feature. And even if the backlink URL leads to 404 or an unrelated site, it is helpful, because it is an indicator that the project is abandoned and if I want to continue using it, I may have to maintain it myself.
The license file is IMHO not the right place to put contact information. If you're community has standardized on the ISC License, please continue to use the recognized version.
Each free software project should have a
README.txt with some basic information about the project, including any contact information you want to give your users. If your project does not have it, I suggest you create it and put the backlink URL there.
As for this part of your question:
such that most or all deployments would be prohibited from removing a backlink?
You shouldn't worry about this. No serious developer will even think about removing this information as long as it is useful. Having some means to get in touch with the project's "home base" is treasured by free software developers. The link will not be deleted until it returns 404 or point to some cybersquatter's porn site.