Heritics! lol, that would be pretty cool though, like walking on water to the apostle paul, though idk how you make it look like paul began to sink...(if you even know about that at all

) Anyways, to walk on water you first must have 'walkable null' terrrain near the water. This 'null' terrain is a certain tile that is all black found in scmd2 and other editors. Then, when you go onto the null, you can walk onto any unwalkable terrin(ie. water, mountain sides ect.).
And there you have it Walkable water!
(make jesus a civ)
ADDITION:
One more thing... once the unit walks onto 'walkable terrain' such as dirt, it cannot go back onto the water without going back onto the 'null' terrain...
Though this technique is pretty sweet, it doesn't look very good sometimes because the units freak out and you can't move them in a direct line.(similar to when a scv builds itself into unwalkable terrain, it randomly moves itself untill it gets onto 'walkable terrain')