Try these (search through wle catalog) W160, W280
theyre big enough to fit your three section staff nicely and will hardly break the wallet.
I know you were looking for one without a zipper, but if those don't work you can always buy some thick material from your local thread/sewing store and have some random grandma there make you one with a tie off flap.
Its what i asked my grandmother to do for me, and i quite like it.
It is better to unlock a door than to crash through it.