Just about every ISP in the world, from the backbone providers to small ISPs in Pakistan, has the capability. More often than not, it happens by 'accident'. http://www.renesys.com/blog/2008/02/pakistan_hijacks_youtube...

If you were very selective about it, and pulled it off without any disruption, you could get away without anyone noticing. Or, do it from a third-world ISP, and say "It was an accident whaduyagonnadoaboutit".