An excellent point, but nothing's built-in like this. You can create a token as you suggest -- in fact that's one of the ways people template out their programs.
Dang! Yeah, we've been using tokens to update URLs in one spot instead of 10.
I was hoping I might even be able to get rid of that step!
ALthough, as Sanford suggests, you can (should) use a token, you will have to pay attention to change the value of this token after cloning the program.
It's one of the purposes of this idea URL Token type in Programs to offer a strong, cloning safe, way to link to LP's