A addon that contains block textures and models from better than adventure (a 1.7.3 beta mod)
BTA is a mod that is a alternative timeline mod that aims to update 1.7.3 with the idea of being a parallel to Minecraft's adventure update, hence the mod name.
The addon will contain blocks and other misc from that mod, such as colored planks, trommels, snowmen, glass trapdoors, flags, and other content the mod has.
It could also contain a world importer, akin to the one included already, but for the mod's worlds. (that also means having a thingy that imports beta 1.7.3 worlds, so you might need to figure that out in some way if it doesn't already do that.)
Jus a suggestion related to my favorite mod BTA. (I Love BTA)