According to wiki https://en.wikipedia.org/wiki/Sukhoi_Su-27, there are two in private ownership in the US. It's been in service since the mid-80s so not so new, and not surprisingly available outside Russia.
Reminds of a scene in JAG where the main characters, 2 US military officers, steal a Russian jet. The Russians wonder why they stole the plane, as they could have just bought it. [1] I miss that show.
[1] https://youtu.be/Ei9KEF7OsKQ?t=2m