Having read http://en.wikipedia.org/wiki/Bicameralism_(psychology) , a few thoughts ...

Classical psychedelics like LSD tend to impart hallucinations which are reinterpretations of familiar objects: hearing a song in the sound of flowing water perhaps, rather than a disembodied voice dispensing commands; seeing a cloud as an intricate organism dripping with lacework skirts drifting in the eddies of an invisible current, rather than a creature standing in the middle of the room with no basis at all in reality.

Furthermore, it's generally pretty obvious to those involved that what they're seeing is an "hallucination"; the deliriants, such as scopalomine, are another story, and an altogether more terrifying class of drug.

Bicameralism's emphasis on bona fide auditory hallucinations, especially disembodied voices issuing commands, is quite distinct from the subjective experience of most psychotropics; the inhibited self-awareness and metareflective capacity described by the article - the "zombie mind" - is almost the opposite of a trip, where every perception seems saturated to the point of overflow with deep, often autobiographical, meaning.

What you're suggesting bears some similarity to the writings of Aldous Huxley:

""One explanatory model for the experiences provoked by hallucinogens is the "reducing valve" concept, first articulated in Aldous Huxley's book The Doors of Perception.[7] In this view, the drugs disable the brain's "filtering" ability to selectively prevent certain perceptions, emotions, memories and thoughts from ever reaching the conscious mind.""

http://en.wikipedia.org/wiki/Hallucinogen#Psychedelics_.28cl...

In summary, I'd suggest that it's quite possible that inter-hemisphere communication is increased, but certainly so is the way the entire brain functions.