Well, I made black rice sake. Grew a batch of koji using black rice and regular rice at the same time so I could tell the black rice koji was done
After about 6 months in refrigeration it's still pretty good. The aroma is fragrant nutty/flowery with fruit (sorry, generic words ... its quite complex) and flavor is a little bit thin, but very nice. Its has quite a bit of umai.
I'll post some picks sometime.