Use a rotation mode instead of having separate top and log blocks for wood and cacti.

[IntegratedQuantum]

[archbirdplus]

Do you intend to gracefully handle multiple block thick trunks with log rotation?

[IntegratedQuantum]

No, in my opinion that would be too many things at once. And you'd also need textures for multi block logs too.
I think that should be handled by a separate block, or is it even worth handling at all? e.g. thaumcraft's large trees also just use normal logs and no one cares.

[du82]

I have issue with this because I want to build with the ends of the logs as their own texture, and directionally as well.