My problem with the way this question was originally posed is that it seems to ask for a correlation between two kinds of things each of which seems much too complex and diverse to permit that kind of correlation.
So on the on hand, we've got this notion `body type', but I've never really understood just what this broad-brush notion, with its coarse packaging of a very complex phenomenon, actually buys you. People can be tall or short, lightly or heavily built, very quick or rather slow in their reaction times, fast or slow metabolically,.... the list goes on and on, and the point is, there's no clear linkage among these binary choices: you can be tall, lightly built, slow-reflexed with an average metabolism, or short, lightly built, quick-reflexed with a slow metabolism, or... or virtually any combination of these `menu choices'. In the face of this kind of human variety, the simplistic division I've seen here and there into endomorphic, mesomorphic and ectomorphic body types seems as arbitrary and biogenetically pointless as the old racial division into Caucasic, Negroid and Mongolian left over from bad nineteenth century physical anthropology which still sometimes surfaces on official forms, but which were know among geneticists more than half a century ago to be biologically spurious. There are very quick endomorphs with low blood pressure and painfully slow ectomorphs who suffer from Type II diabetes, and everything in between.
And on the other hand, we have a huge range of martial arts, each of which involves techniques requiring (or seriously benefiting from) quickness in certain cases, power in other cases, raw strength in still other cases, and complex balance and flexibility skills that are hard to correlate with body shapes/sizes/neurological properties/etc. in any simple way. The example of Olympic TKD that was brought up earlier strikes me as something of a red herring: given the rather artificial point scoring system in that sport, which has made the description `foot-tag' into a truism, a longer-limbed practitioner has a certain advantage, all other things being equal (which is of course very rarely the case). But I've seen absolutely fearsome TKD fighters—the kind of people whose application of their art would win the approval of serious pavement warriors—of every physical description: short, tall, lean, heavy....
Trying to force a linkage between a simplified picture of human physical capabilities on the one hand and the often formulaic descriptions of particular martial arts on the other doesn't seem to me likely to lead to any conclusions you could take to the bank. I think a more realistic way to see it is that there will be a dozen somewhat different karates associated respectively with a dozen different karatekas, and for each of those karatekas, the karate that s/he practices is the right martial art for his or her `body type' (whatever that really is)—but they'll all share a single combat strategy and repertoire of techniques based on fundamental martial principles which constitutes the essence of karate as a martial art. And the one who does best in a brutal physical altercation with an aggressive assailant will be the one who's trained hardest and most realistically for that situation. And the same with TKD, or Wing Chun, or Arnis, or...........
