[R] "Longer Dash" using lty

[Jason Rupert]

By any chance is there a way to make the lty dashes longer?  

Ideally it would work kind of like the following: 
plot(-4:4, -4:4, type = "n")
abline(-5,-4:4, lty="dashed")
abline(-2,-4:4, lty="longdash") # long dash words (love this)
abline(-4:4,-4:4, lty="longerdash")

I read the lty documentation that is included with par, but it did not mention a method for changing the length of the current dash to "longer".

Thank you for any feedback.