Im certainly not the best one to give you advice since i lack experience, but this is what i would do. I would try to anlayze these interviews... try to compare yourself to those who succeeded - what did you do differently... what did those people had in common (smth in appearance, attidute etc-etc). Its nothing wrong with being different, but also you could discover your "mistake" and learn from others. Also - which sort of people failed - any parallels between them? What do you think could have been fatal to you...
Just be positive - if you want the job bad enough - you will get it... eventually! Just keep trying...