Have you considered pennies? It's unique and cheap.

What about stained concrete?

Anyone have a concrete span table for regular mix stuff you buy at the store? All I found was for precast panels and such. Looking for verification that it could span 8' at typical countertop thickness.

With a complete custom steel support frame underneath it, concrete or stone could span 8'. But you are really asking the Impossible for most counter materials suitable for exterior use. Even wood would need more attachment points than every 8', and you'd have lots of warpage issues with pressure treated at that span.

Your right Sophie... Most outdoor tops I see have continuous support. I guess I should be asking more for what can I use that will have a more open airy look and won't be a bother kicking our feet into for support.