The package pkgmaker provides implementeations of features commonly used when developing R packages:
Package specific options, with the possibility of defining multiple subsets
Multiple registries based on the registry package
Unified environment/namespace access functions that work in both production mode (build/check/install) and development mode, when loading code with the package devtools.
The package pkgmaker is available from CRAN at https://cran.r-project.org/web/packages/pkgmaker. The development project is hosted on GitHub at https://github.com/renozao/pkgmaker.