I am quite pleased to have found a thread online discussing this matter seriously. I tried to bring it up on Reddit, but none of the INTPs seemed to relate. My problem is that I tend to type as an INTJ when I actually take an MBTI test, no matter what online version I try. However, I do relate more to the INTP description.
From what I've observed INTJ tend to come up with conclusions much faster due to their intuitive leaps of faith. However, I tend to suspend judgement for a long time. Sometimes suspending judgement up to years, before I make up my mind about a subject matter. When I do finally grasp a higher understanding I am filled with joy. In any case, I think I might relate to the INTP-OCPD archetype, I also relate to ADD. But, I think both of these perceived relations are due to [my] high functioning autism or Asperger, whatever you want to call it. In fact, Asperger can be misdiagnosed as ADD and vice-versa.
Also, based on some studies I read a while ago OCPD traits overlap the traits of Asperger. My best explanation so far is that I am borderline J and P. I even tried some big-5 algorithms that type you based on the verbiage and vernacular one uses in personal writing. Needless to say, I am not very trusting of these algorithms since they are quite simplistic, but I did get conscientiousness on 60% a few times, sometimes 40%, and also 0%.
The more "abstract" and "creative" my writing was the less conscientiousness it got, hence my scepticism of the algorithm. There were also other reasons for why the algorithm wasn't strong, another being that it was based on weak studies from the nineties.
However, with this in mind, I most definitely relate to what other people have said in regards to having a quasi-split personality when it comes to the judging tendencies fighting with the perceiving tendencies. It does give a sort of Robert Pirsig split personality atmosphere, is this the result when pure thinking goes too far? Does one start to develop a second internal entity, an entity created out of pure thought? Thought itself as the building blocks?
Is this, the phenomenon of the "INTP-OCPD", a result of higher intelligence compared to most INTx types? Is this when meta-thinking goes too far? Or is the difficulty in figuring this out a result of the OCPD desire for perfectionism? That is suspending judgement for such a long time, that one starts to develop a second personality that can be used as an anchoring point of orientation.
I don't know, and I am still trying to figure out the predicament I find myself in. Again I am glad to have found other INTPs that relate.