Russians are smart, in terms of defensive capabilities China became China because of Russia (USSR), India became India because of Russia. China is a big headache for USA, which became so because of Russia.
Reading all the posts here I got 3 points :-
1. Russia won't feed Pakistan as Pakistan is a "subsidy" based economy.
2. India's leverage (nuisance value) will make it hard for pakistan to get any "important" deal.
3. Russia has supported the Indian draft of CCIT in UN against terrorism, so it would be not so easy for pakistan to get the deals.
Arms are not sold without any strategy, what strategy could be interpreted with providing weapons to a terrorist state (about to be declared so). Pakistan is soon to be tight cornered in the issue of terrorism, so no one would like to be seen beside them. If China(all weather friend) is not giving pakis their copied SUs then why Russians?