Vine's primary differentiating factor was 6 second looping videos. While the Twitter platform certainly supports video, it doesn't have the kind of automatic, looping, addictive format that Vine was good for.
I think the issue might be that Boomerang has taken on Vine's role here, and is more suited on the back of close Instagram/Facebook integration, whereas Vine is quite separate from Twitter.
Focusing on getting something like this into Twitter itself might be a better bet (though I suspect Facebook has it wrapped up for now).
