Knock yourself out -- assuming you can mange to hit yourself after you've got all this melee defense.
If we are to die, let us die like men. -- Patrick Cleburne
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The rule is that they must be loved. --Jayne Fynes-Clinton, Death of an Abandoned Dog
There are quite a few that improve melee defense. (Note: That link includes +s/l def sets, since they offer half their value as melee def.)
If you have MIDs, you can also use its built in set bonus finder: Window->Set Bonus Finder.
What set IOs have melee defence as a bonus?
The only ones I can think of are:
Touch of Deaths
Obliterations
Can anyone else think of anymore? And do any of the pvp IOs have melee defence as a pve bonus? This doesnt include the steadfast +3% def and the pvp IO +3% def.