I have proper-lengthified the Sunhallowed and Bloodcursed elven arrows from Dawnguard, now available in the Optional Files section. Additionally, I have made an optional replacer that replaces the regular Elven arrows with one adapted from these two. I did it for three reasons: first, to make the normal elven arrows look like the special ones. Second, because the metal fletching didn't make sense to me on the original elven arrows. Thirdly... have you looked at the elven arrow heads? Where's the edge? There's only a point. The edges are BLUNT. The quiver casing is still the original texture, though.

Additionally, these two both pack a corrected normal map for the sunhallowed/new regular elven arrows. They seem to have forgotten to put in a specular alpha, so I adapted one from a combination of the enviro cube mask texture and from the bloodcursed arrow normals. If prompted, overwrite. They're the same. This texture may eventually find its way into the Unofficial Dawnguard Patch in any case.