Bows to your Greater Exp.:

Hi, I'm new here. Anyway to the point:

As a learning experience, I'm wonder how I could create a undead grave digger unit that uses corpses to dig graves and after a "gestation" period would be able to yield a zombie destroying the grave. Things like the units damage, speed, training(well one thing I can't figure out on that), look are easy enough to figure out.
My main problem is basically the grave digging part, the unit should:
1)Pick up 1(and only to be able to carry 1) corpse.
2)Take X number of seconds to dig (or "summon") the grave and when complete have a grave placed and no longer have that corpse. The GraveDigger has to stand there digging it.
3)get another corpse, repeat steps 1 and 2
misc)It would be nice if this ability was AutoCast.

the grave should:
1)be a unit(that doesn’t take up any supply) so multiple grave can be selected and has no base.
2)leave behind and single spot of blight just big enough for a zombie to stand on and be noticed.
3)After a "gestation" period of X seconds be able to raise a zombie on players command (i.e. select it and push the little button that says "raise zombie")
4)when the zombie is raised that grave is destroyed leaving behind the spot of blight.
5) multiple grave can be selected and do the raise zombie thing all at once but doesn't raise any zombies that go over the supply cap (it just leaves the grave or graves that would go over the supply limit there).

Misc:
i)Get the GraveDigger to build at the Grave Yard with its icon appearing in the lower left corner of the icon field not displacing any other icons.
ii)Please no in the map scripting solutions.
iii)And yes I know Warlords BattleCry did something like this.

From the various tutorials and forums I've scanned through (this, WarCraftiii.net, war3pub, infocepter) it seem that these abilities are not current doable to the knowledge of the moding community, but most of you know more about this that I do so I bow to your greater experience and await an answer. :D

Please forgive my poor grammar and spelling.