I have seen hexes in marble, but have no clue where. I have been shopping for a marble basketweave for our master bath and hex tiles for our kitchen. Many companies make those options. I have not seen the hex in marble much, but am fairly sure I did see that more than once.
I just googled marble hex tiles and came up with a bunch. Hopefully, problem solved.
Whatever you do, esp with boys, do not go with white grout... just sayin'....

Here is a link that might be useful: google search

You may, depending on the ages of the kids, want to go with ceramic mosaics for now, and then redo it with marble at a later date.

The Tile Shop has black and white hex tiles and also a black and white plaid tile. Jeffery Court makes a hex carrara marble tile with black diamonds, which you can special order from the Home Depot.

Jeffrey Court Marble

Tile Shop Porcelain

I am doing a hall/guest bathroom, which also serves as the "boys" bathroom when my two sons are at home. I will be doing a black and white floor with a carrara look alike marble in the bath/shower surround. I did opt for a carrara marble countertop. I think the ceramic and porcelain will be easier to maintain with growing boys. Even with grown boys, they don't like to clean up, so guess who ends up cleaning the bathroom :-(.

HTH

Thanks so much for the responses.
I have been able to find solid color hex in marble, but not the black and white pattern.

If I decide to go the ceramic/porcelain black/white route, can anyone recommend a manufacturer/brands?

Thanks again - this forum has been very helpful!

Here's some stuff from Home Depot's website.

Here is a link that might be useful: Home Depot Hex tile