In Assignment: Earth, the Assigners used a transporter to transport Gary Seven 7 a thousand light years to Earth. Using information from the series "Enterprise", Qo'noS was within a ninety light years of Earth.
I think it would be possible if you have sensors that can scan across the galaxy or at least from one star system to another (or you can open a wormhole, like Stargate, and scan the other side of the wormhole for a safe landing site). If you can do that though they you could just beam the Klingon emperor off his homeworld or, even easier, beam weapons of mass destruction to get rid of that pesky ship at the edge of your space before it even knows it's in danger. It a really, really poorly thought out technology and sheer arrogance to suggest that only humans would come up with it.