disclosure: I work with robertk at Avant, where we've developed syberia and lockbox specifically to have reproducible model builds and to turn R model objects into API servers in a deterministic way. Lockbox is closely modelled after ruby's bundler, and syberia is like rails for data science. I've you've ever written a ruby-on-rails or a django app you'll feel like at home using lockbox. I encourage you to give it a try, and let us know in github issues if you are having any trouble using it