Welcome to WebmasterWorld Guest from 126.96.36.199
An important question is this - why would a webmaster care about more frequent crawling if the page hasn't been changed anyway? Most sites I see are crawled much more frequently than the pages are updated anyway.
I have 21 categories and post about 250+ articles a day, which are evenly time delayed... hence more than one every six minutes.
BTW, I accomplished this with relatively low PR (4).