A new unit for the vampires you say?
Hmm..
Something to do with frost wolves was also my first reaction.
An idea I always liked, and what I am planning on building myself, is a flesh golem/undead constructy thingy.
Basically, think Pudge from Dota (or at least the undead abomination from WC III). One can easily theme it
to any climate (ice creature or swamp thing etc.) he would kind of be like a slow varghulf(like) tank.
I was thinking of making this as a champion for crypt horrors and then converting an empire engineer into
my Dr. Frankenstein :zombie:
But me and my friends have had considerable discussions on the dwarves and what we would like to see in their army. We were discussing what the dwarves will need to make a viable non-shooting army, thus more mobile. And this is what we came up with

your friend might like them)
- Dwarves riding bears:
basically an ironbreaker/hammerer riding a bear. It would be slow monstrous cav (M6?)
But heavily armoured and packing a punch.
- Dwarves on mountain goats!
Sounds silly, but hear me out. They would basically be rangers riding mountain goats (imagine big ram with massive curly horns). This would be their 'fast cav' so also make them M6, but give them the fast cav rule, and as they are rangers, they can have great weapons and crossbows... could be nice.
- And then add a master rune: Something like the Master rune of the wrathful or scout or something or some such.
Basically it provides all warriors, longbeards and rangers the vanguard move. Closing the distance and making your army that much more mobile. Fluff would be that only certain impetuous dwarves are allowed this rune. And then they spur the army onwards as quickly as possible to the enemy. Or something like that
Sorry, went kind off of on a tangent there. Anyway, hope it helps.