I wonder if one could simply use LaTeX \\newpage command in R markdown v2 in a different way than this:
\\newpage
```{r, results=\'asis\', echo=FALSE} cat
In the initialization chunk I define a function
pagebreak <- function() { if(knitr::is_latex_output()) return("\\newpage") else return('') }
In the markdown part where I want to insert a page break, I type
`r pagebreak()`