OK, I found the cite we were talking about earlier. Charlotte Zeepvat, The Camera and the Tsars, page 105.
For those who do not have the book, here is the paragraph, in full:
One of the first to rebel was Nikolai Konstantinovich. Ignoring his mother's attempts to find him a suitable bride, Nikolai lavished his fortune on his mistress and his art collection. By 1874 he was stealing from the family: when this emerged he was declared insane, stripped of his rank and placed under supervision--but wherever he was taken, trouble followed. In 1874 and in 1876 a woman who should not have even come near him became pregnant by him; in 1878, in Orenburg, he married another woman in secret, and all the time he preached revolution. Officially he ceased to exist and, in the summer of 1881, Alexander III sent him into exile in Tashkent. In 1895, though still living with his wife, he bought a sixteen-year-old Cossack girl and started a family with her, In 1900 he contracted a bigamous marriage with a schoolgirl which was quickly annulled. Visiting him in 1904, his sister Olga said 'he has completely lost any moral sense of what can be done and what can be demanded.' But there was another side to Nikolai. He took a serious interest in Central Asia, organising scientific expeditions and publishing his findings. In Tashkent he launched irrigation schemes and other beneficial projects. He welcomed the Revolution, and when he died of pulmonary disease in April 1918, local Bolsheviks arranged a grand funeral for him in Tashkent Cathedral.
Whew! A lot of typing. Reviewing my post, I will admit that Zeepvat did not say N.K.'s name was removed from the rolls of the family, that was my take on it; but she does say he was stripped of his rank and officially ceased to exist. Perhaps I am just taking too literal a reading of her?
Regardless, he certainly seems to have been one of the more colorful Konstantinovichi.
Best,
Jane