u will be pushed to get 30e i think on a prot moded staff, as most people will want to mod it 40/20 but wont be able to. i'm gunna say 100k if you find the right buyer.
yes, i have a couple mixed attribute/20% prot celestial staffs, same rarity cathan old school type of staff and valued in the 20-30e range, so xxxe is totally wrong, think 20-30e. i would do this: go back to the person who pc'd at xxx and tell them you need fast money and you will make them a heck of a powertrading opportunity and offer it to them at 50-60e. ;-)