Has anyone tried taking 4 etheral vamps on one flank in amongst wraiths ( for magical protection ) to roll an enemies flank whilst ghouls and grave guard occupy the centre?

Never. Not that I didn't consider it. I just think something like that would be too expensive. One guy with magic weapon or a single strong spell could easily cripple the expensive ethereal unit.

And there's steadfast - wraiths with a couple vampires will have to kill a lot in order to break enemy units so I would't count on a quick victory on the flank.

Take 5 Wraith heroes, put them in the front of Ghouls or Skellies without command group. Now you have a pretty nice flank unit.

Those five wraith heroes with chill grip would certainly cripple a steam tank in no time. Five attacks auto hit - auto wound, no armour saves. Bye bye steam tank. Is this right? - in a sense of am I correct, forget about the sports on that if they a sporting two stanks!