Asking, or seeing if its possible, to write a plugin that creates a sign at the position the player logged out from. The sign would remain in place until the user re-joins server. The sign would display user name and time logged out. Plugin could also leave server time and date on sign (optional)
We use Warpz0r on my server and it allows people to build on /warp points and /home locations and when you come into them you are dying from being in blocks and have to try to find your way out. It would be VERY useful to have a empty space to come into to know you won't die on log in.