I used black rice in different recipes. It clearly take longer to cook than normal rice, the grains remain separate and its generally harder than normal rice (I would say something similar to wild rice, but more mealy).
As you said, it's not suitable for risotto per se, but I once made a risotto with normal rice and almost at the end of the cooking I added some (already cooked) black rice, which added a nice color and texture.
The taste is quite strong, so you might want to avoid foods that are too mild in taste. A good combination for me is with peppers, olives and feta cheese, possibly mixed together in a cold rice salad.
Since I'm not sure how to re-post as my guest account, I just want to say that I tried a little variation after reading logophobe's answer stating that he thought an added oil would counteract the chalkiness.
I toasted the rice grains (as the linked article stated) before soaking them, and then after blending, I strained the resulting milk once, and then threw the strained liquid back in the blender and added some canola oil, and the result was a MUCH better texture overall.
I didn't have Xanthan or Guar gum on hand to try, so I'm still yet to see how the mixture will hold up in the fridge, and if stirring will be enough to keep it this texture.
It definitely needed some sort of sweetener still though (in my opinion, but that's probably up to preference), but I feel like the oil, and possibly the toasting, really affected the texture in a positive way, to where it's a much more palatable base.
Best Answer
The following excerpt answers questions 1 and 2. Additionally it reduces the cooking time for the parboiled rice.
There are several techniques you can use to prevent unprocessed cooked rice from sticking to each other:
Source: The Science of Cooking Rice