Haven't thought about that - will look into it, as it sounds interesting and useful.
This doesn't work for me, as I am mis-using the package structure - see below.
I am (mis)using the package structure to do reproducible research and to make the archiving, sharing and versioning easier (on github).
I am using the R folder for function definitions, data for input data, and R notebooks stored is inst/Reports for doing the import, processing, analysis, and graphing of the results. E.g, one import notebook imports data, processes ot and writes it into the data folder, so that when I load the package again via devtools::load_all() the new data is loaded.
So the idea is not that much install it, but to use it with devtools to do analysis.
Following that, I am using Makefiles to automate the knitting of the reports, i.e. importing and processing the data, creating graphs, ... So it has nothing to do with the actual building of the package (which is done in the usual R way), but with the actual analysis.