I remember reading about person (maybe in Poland?) who liberated his slaves and created a city of freed slaves, which turned out to be so prosperous in time that it was envied by the Russian Empire and was destroyed with a military operation. What I recall might be partially wrong. Could somebody give more information and sources about these events?
Not slaves, but peasants serfs. There was no slavery in XIXth century in Russia. Not much difference in practice, though.
It was in Sztabin, Poland (then in Russia), the noble freeing the peasants was Karol Brzostowski, and it was called "Rzeczpospolita Sztabińska" (Respublic [or Commonwealth] of Sztabin).
I couldn't find English source, here's a Polish article about that:
http://www.konflikty.pl/historia/1815-1918/rzeczpospolita-sztabinska-utopia-na-ziemiach-polskich/
I've read about it in Polish history-popularizating book "Sami sobie" by Stefan Bratkowski, it's hard to find any information in English, even on wikipedia there's only small fragment mentioning that in the Polish version of http://pl.wikipedia.org/wiki/Sztabin article.
Edit: a small fragment in English is here http://ltpl.eu/en/community/sztabin-en
Also found 2 book about the hrabia Brzostowski, but in Polish (beware of books published in Poland between 1945 and 1989 - a lot of communist propaganda and this is great subject for it, so take the informations with a grain of salt):
http://www.alibris.com/search/books/isbn/9781232683797 http://catalog.hathitrust.org/Record/000755318