I searched for this and found that with {grid} there are ways to rotate an image, and that for some plots you can play with their rotation (for example plot(x,y) instead of
It's kind of possible via the gridGraphics package, although it feels a bit rough on the edges (the examples in ?grid.echo don't all work for me),
plot(1:10, rnorm(10))
library(gridGraphics)
grab_grob <- function(){
grid.echo()
grid.grab()
}
g <- grab_grob()
grid.newpage()
pushViewport(viewport(width=0.7,angle=30))
grid.draw(g)