If you have nothing to build and your things aren't going to be redistributed, you'd better write a simple shell script ihmo.
But if you really want to do a .eopkg, just do what your shell script would do but in the install section of the package... something like this for example, but that's the hard way and it and it makes it non portable since unlike a shell script that could basically run on any distro, the .eopkg will work only on Solus.