is there such thing as....

is there such thing as a max dmg vampiric necro staff?

There is no vampiric mod for any staff, sadly.

is there like a green item which has it in it

No, there isn't a Vampiric mod for a staff in any shape or form.

what about the wand type can that be vamperic

No.
Vampiric is only available to Swords, Axes, Hammers and Bows. Not wands, staves, rods or focus items. I think that covers all the bases?

If it doesn't exist as an available mod to a normal weapon, you won't ever find it on a green item that can be modded.

Well I remember an early collectors/reward staff with Armour Penetration, but I've never heard of a vampiric staff.

Eh if staffs have vamp on it, it would be to OVERPOWERED, Halls of Heros will be overunned with wand vamp spiking.

This is why no other than regular weapons like axe/sword/hammer/bow has a vamp.