Hi Sebastian. I really like the idea behind OpenMeta, and do plan to support it or something comparable. The reason I've held off for now is that there was some disagreement between other Mac developers about the best way to implement it, so that it's compatible and less likely to break if Apple changes anything in the future.
I'll catch up with where the project is and plan for support in a future version of Clipstart.
Clipstart also has AppleScript support now, so that may be another option for getting tags and adding them to other applications. I don't think Leap's tags are scriptable, though.
Let me know if you have any other suggestions.