The production Invader Zim figures weren't even out when I started picking up prototypes for the line, but thanks to the fact that Palisades ebays off many pre-production items, I was able to pick up some cool stuff. 

Something I love to find are two ups.  These are particularly tough to come by though, but look great next to the final, smaller pieces.  This first item is a two up of Dib, used as a tour sample by Palisades.  The final sculpt will be quite a bit different, with changes to the torso, forehead, eyes and hair.  He comes on a nifty little stand, and actually comes almost completely apart.

My second Zim pre-production item is also a two up, this time of one of the three heads for the Zim figure.  There are three variant heads for Zim, and rather than placing all three on bodies, they simply sculpted heads at about 200% the final size, and placed them on special stands.  You can see from the shot with the Mattel Batman just how large this is.

This next photo is of another tour sample, this time of the regular Ms. Bitters.  I have her shot with the Hot Topic version right now, since that's all that's currently out.  She's about 25% bigger than a regular figure, and came with the same nifty purple base.

Notice the marked difference in her hair.  On the left is the production Hot Topic version, on the right is the regular prototype version.  There are also major differences in the legs and final paint ops.