Package brms by Paul Bürkner (https://github.com/paul-buerkner/brms) is an elegant complement to rstanarm with a large selection of models. The main drawback is that it there are no pre-compiled models as with rstanarm, so running a model requires frequent recompiles.
Following a concept of Paul I have created a demo package brmspack to show how to use brms in a package with model compiled during installation.
Some of these steps are going to get a bit easier with the next version of rstantools. If you add
SystemRequirements: GNU make
to DESCRIPTION, then src/Makevars can use syntax that works everywhere but Solaris and even works on Solaris if gmake is installed. So, you can do things like
SOURCES = $(wildcard stan_files/*.stan)
and not have to explicitly list the Stan programs that you want to compile.
… and tested the GNU make suggestion with current github, works - see branch in brmspack. Too bad it generates a NOTE on CRAN; I have asked Uwe what he thinks about this.