I had found this blurb on Wikipedia myself when researching the Ingo Swan OBE experiment.
Note that it says:
"Swann wrote that he was aware of most of the objects on shelf above his head, but he did not know it held four numbers on a side. A side that would not have been visible if a reflecting surface had been angled near the end. "
Hence, even if Swan did use the drawing board as an extension, he could not get at the target. Further research on this experiment confirms this to be the case:
in 1971 Karlis Osis began to plan OBE research at the American SPR, One of the first subjects to be tested there was Ingo Swann, who went to the laboratory two or three times a week where Janet Mitchell tested him to see whether he could identify a target placed out of sight. A platform was suspended from the ceiling about 10 feet above the ground and divided into two. On either side of a partition various objects were placed and Swann was asked to try to travel up to see them. The reason for the partition was to see whether Swann would identify the correct target for the position in which he claimed it to be. Bright colors and clear familiar shapes seemed most successful and glossy pictures or glass did not work well for the experimental purposes.
After his OBE, Swann usually made drawings of what he had ‘seen.’ Although these drawings were far from perfect renderings of the original objects, they were similar enough that when eight sets of targets and respondes were given to an independent judge she correctly matched every pair; a result which is likely to happen by chance only once in about 40,000 times [Mit73].
The results of all these experiment were most encouraging.
http://www.nderf.org/obe_dream_faqs_nde ... OB_vision_
Thus the theory of using his drawing board as an extension with a mirror can be ruled out owing the fact that the targets would not have been visible due the height and partition. Moreover, Ingo Swaan is a credible subject, and has been investigated by many reputed scientists and subjected to vigorous tests. However, having said all of this, I still will only take this experiment as being suggestive of the reality of OBE, and again not conclusive. Like Dr Tart's study it lacks an observer present in the room or CCTV footage of the test subject and the target is present within the same room as the subject.
I will only accept a study as conclusive if a subject is able to see a target in another location. Now having said that, I will point you to studies that do exactly that:
Other experimenters including Robert Morris at the Psychical Foundation of North Carolina spent two years investigating OBEs. A volunteer subject Keith 'Blue' Harary, who claimed to have been having out of body experiences since childhood, was able to lie down in a sealed laboratory room and project himself to another house twenty yards away. While there he was able to read letters and report accurately on which experimenters were sitting there and where they were sitting.
In the United States, Karlis Osis and Boneita Perskari spent several years doing scientific research with an excellent OBE subject, Alex Tanous, and were able to achieve significant results. One particular test involved Tanous traveling astrally to a different place miles away to visit a particular office to see what was on the table then report back. Tanous did not know that at this office a psychic, Christine Whiting, was waiting to see if she could see anyone coming to visit. With her clairvoyant sight she was able to see Tanous come into the office and as well she described in detail his position and the shirt with rolled-up sleeves and the corduroy pants he was wearing (Williams 1989: 35-36).
French researchers including Professor Richet spent many years having the exteriorized body move material objects, produce raps at a distance and affect photographic plates and calcium screens. They photographed exteriorization.
http://www.victorzammit.com/book/chapter07.html
The late Karlis Osis, of the American Society for Psychical Research, sought to determine whether a physical instrument could detect a psychic's "astral body" at the time he was attempting to view a hidden target through his astral vision. Osis installed a strain gauge (which detects extremely subtle physical movements) in front of an optical device in which a graphic "target" was concealed. The setup was such that the image could only be perceived face-on - from the place where the strain-gauge was located; otherwise, from a different angle, a viewer would only see overlapping lines. The psychic Alex Tannous, who was not told about the strain gauge, was asked to attempt to project in front of the optical apparatus, and describe what he saw. Osis found that the strain gauge registered significantly more movement in those trials in which Tannous gave correct descriptions of the target. The implication may be that some facet of Tannous' mind was indeed "projecting" in front of the optical apparatus.
In the mid-1970s, Dr. Robert Morris and his colleagues conducted an interesting experiment with psi researcher Keith Harary as subject. Like Miss Z, Harary - at the time a psychology student - seemed able to voluntarily induce an OBE. His kitten, enclosed in a cage and constantly filmed, was to act as a biological detector of Harary, who would attempt to 'project' his consciousness into the cage from a distant room. Indeed, it was found that the kitten's agitation - its movements in the cage - was significantly reduced specifically at the moments at which Harary had been instructed to project his consciousness into the cage. Over time, however, the kitten's "baseline agitation" decreased, and its reactions to Keith Harary seem to have declined - perhaps as it became habituated to the experimental conditions (i.e., being locked in a cage!)
http://www.parapsych.org/out_of_body_experiences.htm
In all these studies I have mentioned there are sufficient controls and all involve the subject having to project to another location to see a target/s, they also involve some kind of detector at the location to detect the astral body. These are therefore conclusive studies for the reality of astral projection.