I'm sure this has been done many, many times. But I did a Namus search for people who disappeared within a four year period who seemed to matchup. Nothing particularly interesting, but the only ones who even resemble the sketch (other than Lepsy and Wilson) are:
William Ellis, disappeared in June 1971 from Maryland at age 38. I like this guy's look ALOT. He seems to have something weird with his bottom lip (which I believe was mentioned by one or both of the stews). His droopy eyes very much resemble Comp B.
But alas! His file has him at 5'6, 150 lbs. Booooo
Lewis Welch, disappeared in May 1971 from Northern California (Nevada County specifically) at the age of 44. He was 6'2.
But alas! He had auburn colored hair. His friends think he killed himself (jumping out of a 727 could accomplish that if he wanted to)
James Shaw, disappeared in May 1971 in Nevada at the age of 41.
But alas! He was 6'4 and someone that tall would surely have been commented on by everyone who saw him.
Charles Hollingsworth disappeared in October 1970 from outside Sacramento, CA at age 39. He was a doctor. He was 6'1, 200-210.
But alas! I don't think he likes much like the sketch and also was a handsome man. I don't think Mitchell would have A) called this guy a geek, or B) thought he could take him in a fight.
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and finally my favorite new suspect! (not really...but maybe...sorta)
John Lake, disappeared in December 1967 from New York City in his late 30's. Would have been 41 at the time of the hijacking. Was 6'0, 180. Was the sports editor for Newsweek at the time. This is from the Doe Network webapge: "Many of Lake's coworkers at Newsweek feel his disappearance was voluntary. He had been depressed for at least a year, due mainly to the deteriorating relationship with his wife and growing dissatisfaction with his job. Despite his high-profile position, he had struggled financially for years. More than a few of Lake's associates thought he just wanted some peace, although none seem to find suicide likely." Also: "He was a runner himself and believed in keeping fit."
With Willie Mays!!