Hadley, can you share a bit more about your plans for modelr and what need(s) the package will be designed to solve? Congrats on your book btw, I've been reading it for a few weeks and it's quite simply excellent.
However, the modelling infrastructure in R is generally showing it's age, and thinking about how to make modelling easier is something that I will be working on in the coming months.
No plans for more FP packages in the near future, although I do want to add multicore and progress bars to purrr.