Ok so this is an idea that builds on this old idea here which mentioned an impossible idea. I thought abput it and wanted to bring this up to make something like this more possible.
1.8 added alternative block textures. I would like to see this for RPG plugins like an old plugin Sponge Energy You could allow plugins to use an alternative block modules to like in Sponge Energy create machines that can use a certain block module from a resourcepack that can be the server resourcepack to create a custom texture for these machines that is only available when that block is used as the machine.
I wanted to improve on my old idea to make it more possible.