Ok take a look at this:
http://forums.ninja250.org/viewtopic.php?p=59764#59764
With these instructions you should be able to eliminate that ugly thing off the back of your bike and integrate your turn signals into the empty pods on the left and right of your brake light. Read the thread and you'll see that the empty pod covers are painted and this guy was able to get the paint off. Then all you'll have to do is make a license plate bracket.