Seeing as how I have exactly no knowledge of programming, I don't know how hard this would be to make, but what would be cool is a bow that uses both arrows and enderpearls, and teleports you to where the arrow lands. I ran a test, the arrow goes about seven blocks further at full charge and the angle I fired (downward), but I know I'm more accurate with a bow.
Not hard at all. It's even possible to make it via commands inside the game. Just don't see what the purpose of that would be...
I use the pearls to navigate the nether a lot when i mine quartz, and the bow is far more accurate than throwing, along with getting a slight bit more distance.
Wouldn't this defeat the purpose of enderpearls? And PvP could get interesting with a bow and enderpearls. =o
Again, I'm not sure if the programming is possible, or easy enough to make it worthwhile, but in my mind, it would still use an ender pearl to TP you. You would need both a pearl and an arrow in your inventory to get it to work.