I'm starting to think maybe I should just put my wb holders up there.
Downtown Detroit by
mmeiser2, on Flickr
They'll just provide a bit of space to keep the bedroll off the handlebar for finger space.
That's from my summer UL road touring setup. No bivy roll necessary.
Of course the only thing I'm going to put up there in the colder climates is my fuel bottle. An empty space might come in handy for temporary storage of drinks I guess.