Hmm...lets See, what all have the Russians stole-
B-29--->The Tu-85
F-15---->Their Mig29 looks an awful lot like the Eagle
The Blackjack
Countless other aircraft designs, but those are the ones I could think of.
Also, think back to WWII weapon design. Doesnt the Kaleshnikov rifles look a lot like the German StG 44?
http://en.wikipedia.org/wiki/StG_44
Honestly, name me one thing that the Russians havent in some way copied?
What you've got to remember also, is that Russia, for it's size, has a HORRIBLE economy. Remember how they just left multi-million dollar attack submarines (Nuclear Powered at that) sitting in port unmaintained? And now they cant be used again. They would probably be able to build maybe 4 of these and say enough because they dont have the $ to do it. The "Big Bear" is not what it used to be folks.
Happy Flying!
SuperBugz