Said missions can be done but it'd be much better just to wait for multi-maps to be ready for inclusion since the same said missions would need to be programmed for that project. The map method you indicate comes with some issues of its own too, particularly where wrapping around is concerned - works great for flat maps nice and easy though.
+1000 to this. It does not IMO make sense to do all of this coding (and it is quite a large amount of coding to do this), and then junk that all a little while later when the actual Multi-Maps stuff comes along. It would also as you say have issues with world wrapping. All Mapscripts would need to be changed to accommodate this, and then changed back once Multi-Maps come.
All in all I think that Hydro's idea may be more work than it is worth.