Not that I'm particularly looking for airplane registrations/tailnumbers, but the Gazpromavia 737s seem to be the only RA-registered 737 in Russia that I've spotted, all others aww VP, EI...
Not only, also Aurora Airlines.
http://samolety.org/wp-content/uploa...ng-737-5L9.jpg
Together with Gazpromavia totally 6 pcs of 737.
This episode has something to do with investigation of Kazan disaster. MAK prepared the Final report this spring, and classified the disaster as CFIT. After it, the Rosaviacia (agency of Ministry of Transport) started to suggest technical reasons (known low-temperature malfunction of hydraulic system of 737). This is the reason why Final report was not published yet and it is also a background of this episode.
Their roles plays also Boeing and FAA as I noticed before.
The speculations above (switches in tail part, mother, Transaero etc.) are not based on reality, I suppose.