Hallway/building entrance tiles. where to find?

Try googling porcelain hex tile or hexagonal tile. Also google subway tile – not because you want subway tile but because the companies that carry that may carry this. You can get ordinary dark gray and beige hexagonal tile from Home Depot but the pattern is 30s style meant for bathrooms, it has eased edges, and the grout lines are too wide. Also, the colors are off. Visit a tile store. Also, Restoration Tile has pre-made, not custom, basic tile like this, with the prices listed online. In the grand scheme of things, they are not all that expensive. Waterworks and Heath are expensive.

There are companies like this which recreate patterns like your picture, but they are likely as expensive as the companies you mention above:

http://www.restorationtile.com/index.html

There is also the option of making your own patterns or replicating these patterns yourself. In the Bed-Stuy Reno blog here on Brownstoner, the folks renovating their place put together patterns for their bathroom. It was likely time-consuming, though, but what better way to get the exact look you like. Maybe if you contacted them they could give you some tips.

Grand Army, agreed.

Vinca +1.

You are looking for unglazed porcelain tile, flat not eased edges, and very narrow grout lines. You should probably seal it after you lay it, though, to keep the dirt off.

Also do a search on “Victorian encaustic tile.”

American Restoration Tile: http://bit.ly/mKaVHa