Since 1.3 doesn't automatically sort teleport bookmarks alphabetically anymore, but we still seem to lack any way of sorting them manually - how about clicking a destination and just hitting up and down arrows moves them up and down the list?
Hey, whichever works. I just haven't seen any drag=and-drop functionality in Starbound's UI, so I was going with something that looks easiest to implement. Then again, no idea about code.