Provide both shlib and standard versions of R?

That is not true, almost all binaries come with R as shared library -
it is in fact the default on Mac OS X and Windows. Most Linux
distributions provide a shared library binary as well.

This would be good news. But at least, under linux,

./configure --help
  --enable-R-shlib        build the shared/dynamic library 'libR' [no]

This option is not enabled by default.

Bo