Should have a filter on each side to sort items.
Should look similar to other Buffers and have the textrue of the Advanced Filtered Block Extender.
Should be able to set output priority.

So my rotateBlock function in the buffer code might not be useless after all? Or will the input/outputs not be dependent on the buffer's facing direction?

It'll probably use the same system as the Advanced Buffer.

Pushing this to the next release.

This functionality will be present in the upcoming pipes, closing.