it is probably easier to just wrap R functions as a subprocess in python. you would have to write some R code to do this which might involve writing to a flat file. i do this all the time in R wrapping up something like rgf and calling from within R. i have wrapped up python and called it from R using system. the same idea works for python as well. you could probably write some kind of general wrapper that would work for most of R's ML type functions.