My DK Tank geared in all epics (from heroics) except wrists, does around 1100-1200 dps on average. Boss fights usually around 950-1000, trash I can go as high as 1600, instance averages around 1150 usually.

Edit: And I just use a single macro for offense on my tank, plus manually casting DnD at the beginning of each fight. Macro is:

#showtooltip
/cast Rune Strike
/castsequence reset=target Icy Touch,Plague Strike,Blood Boil,Blood Boil,Death Strike

Works good, lots of AoE damage/threat, and Death Strike actually helps quite a lot preventing me from having to heal my tank on 3 and 4 pulls.