"3д порно" gets some existing sites up, probably easy to find an enduser to sell to.
I see a local has the .net. The best would be 3dпорно (d) but you can't mix scripts.
That gets 39,991 wordstat search and 975k google SERP.
http://www.google.com/search?hl=en&r...=&oq=&gs_rfai=
3d порно=
http://www.google.com/search?hl=en&r...=&oq=&gs_rfai=
3д порно/ порно 3д gets only 6963 on the wordstat
http://wordstat.yandex.ru/?cmd=words...geo=&text_geo=