Scientists have done tests on OBErs. I believe the scientist Robert Morris did an experiment that had positive results. Very few have been done and any aspect of parapsychology has been ignored by mainstream science for a long time because it conflicts with there basic assumptions. That the brain creates consciousness.
OBEs takes skill and doing it in a lab probably takes more so you can't expect an obvious amount of research to be done in that area. NDEs (near-death experiences), which are very similar to OBEs, have occurred when there was no brain activity picked up by EEGs and what not. If NDEs are created in the brain then it is likely that when an individual has an NDE there would be at least some gamma brain waves which are always present in conscious experience. Not to mention the fact the integrated and organized experience almost requires at least some frontal lobe activity. None was detectable in most NDEs.
Also look up the case of Pam Reynolds, which is like the smoking gun of documented NDEs.
Michael Prescott's Blog: Irreducible Mind and the NDE
There is also reports of veridical OBEs (if I spelled that right google search it) which are cases when people see another person out of body.
So, is there evidence? Yes. Do most scientists care? No.
link:
Skeptiko - Science at the Tipping Point Scroll down a bit to find a podcast on NDE.