Friday afternoon, got me interested, not a lot to do so off I went...
www.airlinerlist.com
seems to illustrate the following:
Single examples to be found at: Monino, Samara, Vornezh, Ulyanovsk and Sinsheim.
At least five examples seem to be or have been at Zhukovsky, as of last reports. Surely there is a spotter around who can confirm or deny this. This number includes the Tu 144LL operated with NASA.
(Edited by Foxile after Z's post below)