I've never seen any granite that is completely uniform, but I do think AB comes the closest. That's why I chose it for my kitchen. It definitely has a grain to it and a bit of sparkle, but it appears totally black. If you want completely uniform you probably want a solid surface material that can be made that way. I don't think I've seen a soapstone that is completely uniform either.

Black Corian? It's in the A price group, so probably less expensive than granite.

I'm linking you to my finished kitchen. I put leathered absolute black on our perimeter with white macaubus on our island....same concept light patterned island (though my pattern is more linear) and solid perimeter. The absolute black reads as a solid even though there is some interest to it. It's really pretty installed.

Here is a link that might be useful: babs711 finished kitchen