[[The app can be found at: http://spark.rstudio.com/fsmart/RStylizer/]]
The git can be found at: https://github.com/EconometricsBySimulation/Rstylizer
In general the html generated is not very efficient since tags are repeated when css embedded styles is probably the preferred option. However, since it makes very little difference in terms of load time, I figure this should work fine. In addition, Blogger's gui seems to handle the tags better than embedded style sheets.
(I created an outdated git: https://github.com/EconometricsBySimulation/RFormatter as well but could not figure out how to change names so sorry for the messiness.)