Closest you'll get is Ice Patch (from Ice Melee).
Tankers have single target Holds and Immobilizes but AoE Knockdown and Disorient.
the earth epic powers has a AoE stun that might work but don't think it would be very good (takes a while to recharge as well) has an AoE sleep but that's not going to help 
Stone also comes with fault, and SS has hand clap, two nice little disorient powers.
Probably more fun not to depend on Burn too much. It was good, then it got nerfed to hell, now it's best to skip it. Get some nice AoE attacks instead, for both damage and Punchvoke.
Can you get an AoE Hold mite be Cone Imob in the epics? if so burn will work fine?