Unfortunately decent monk gear costs far too much, especially those life on hit weapons. Also weapon alone wont work, needs also LOT of double resist gear... checked AH just, seems dispersion between low and high end gear prices is widening. All starter level inferno gear goes cheaper and cheaper while good gear costs more and more. So even harder to gear monk now. Dont really like how monk talents force to stack double resist gear with both resist all and resist one special, makes finding gear harder. One with Everything talent really should be redesigned.
Btw boss fights are bad example of how easy/hard DH is, for example I personally facerolled Belial with monk, 500 dps LOF weapon (got nothing better with LOF ) + 5 defensive cd and in 3rd phase could just sit on place and rotate defensive cd's eating all boss melee hits, only running for aoe pools... maybe could have tanked them too, did not try. Biggest problem was hand getting tired pressing mouse button that long. In DH it took like 5 hours, switching specs and trying to find one which kills adds fast enough and does enough dps on boss to skip phase2 as fast as possible. Dh farms trash and kills champion backs better than melee but melee has much easier with bosses I thing.
What comes to smokescreen, its not safe to be close to mobs and try to chain it... only 0.5 sec or so between cooldown and next activation, but its enough for close melee mobs to oneshot DH, they react instantly. Dont know if there is gear which allows to chain smokescreen for ever, maybe with hand crossbows and all other possible slots with +discipline it could come effectively close enough.