Had to do a quick read up as I never went passed the necron game exp
http://wh40k.lexicanum.com/wiki/Davian_ThuleSummary.. his blinged up self carried a demon hammer and a melta gun..
Wounded (inc by a tyranid poison) stuck in dreadnought, relative to venerable..but equal in status to a Force commander.
Without any further info IMO-its a shame you can't just call it ironclad.. the melta and hammer combination (and extra toughness/av), along with extra armour and stuff would reflect him really easily?
If going for venerable..I'd say default the multimelta and the CCW most reflects his hammer and his melta...