Perhaps you will find the mode of use, or at least instructive to read. In either case, it is available for your perusal. Comments and feedback welcome. Currently at revision 0.7, rcpp-mode.el is distributed as a single source file. To use this in your environment, either save this in a place that your load-path knows about or use load to evaluate the file explicitly.
Documentation is now available.
The entire package, including source, documentation, and a Makefile to help the medicine go down can be downloaded as a single tarball .