Default For list.len Argument ("list output truncated")

Hello

How can I set a default for the 'list.len' argument in 'str'?

x <- as.data.frame(matrix(1:1000, ncol=1000))
str(x)
formals(str) <- alist(object=, ...=, list.len=1000)
args(str); formals(str)
str(x)

Does not display errors, but does not work either.

Thanks for help

S?ren