He tells you in detail how he does each one, doesn't he? Man, it's been years since I found that site...didn't go back, but I remember checking it out during my spare time in Integrated Computer Applications class four years ago. I've gotta say, I'd have been much happier if the Necrons had gone down the road this guys took them--more mechanical/terminator themed rather then egyptian. More of a mechanical feel rather than undead, you know? I really preferred the old bulky Necron models to the new slighter, more skeletal ones.
As to an entire army, I doubt that even the creator of the site does that; it looks like he still uses standard Immortals and Warriors, but likes to convert vehicles of his own design, though his lord is heavily converted too. Ideas on how to make such things? Have some inside information as to what sort of action figures are out there, or have a look around the internet or the store to find suitable figures to start from, and then begin visualizing what pieces you plan to remove and what you plan to replace them with.
