Add a block to play sounds for structures and/or add a faction-based bard; for use in the structure system.

Block:
Added.
Needs textures/icons
Needs localization entry

NPCs:
Base types added.
Need textures.
Need spawner icons
Need AI
Needs localization entries (lots of them...)

unsure about the trigger for the block. The player range activation is working very well on the Bard but there's a lot of uses for redstone activation as well. Clearly redstone could do both but it's up to you.

Would both be possible (given time constraints)?

Yea, I plan on having both -- a faction NPC bard for use as..well, an NPC bard in structures. And a sound-block that has a few activation features (redstone, players enter range, ??).

The basic function of both will be very similar to the existing bard, as far as adding songs / configuration goes.