discounted price for 5+ cases

Hi, I am looking for an extension to do the following for me.
I would like to show a
price per case (default)
Also a discounted price for 5+ cases
and further discounted price for 10+ cases

I would like to do this on a per product basis as not all of our products are sold by cases.
I've attached a screenshot to show roughly what it is I'm trying to achieve. I'd be very grateful if someone could point me in the right direction.

Thank you

i just had the same question, until I found out it was buildt in feature in 1.5.5.1

On product edit, go to discount tab, there u add 1 discount price for each treshold quantity. They will list nicely on product page, and seem to work nicely on the totals