this is my experiment.

128x128x128 blocks, 8x8x8 entities, ~20fps. if i move to the middle of the scene i get 50-100 fps.

my graphics card is quite slow (radeon 5400) and i guess with this random distribution almost no faces can be removed. with a typical landscape a lot less faces would be necessary but i don't know how yet how to generate landscapes.

edit:
i forgot to mention that this is a7 since a8 seems to have a bug with setting meshes. maybe a8 would be a bit faster?