Ik its hard to coad this thing (its might be inposable) but if you do /os lb edit [ID] model [model URL] you can set up a custom block model 

+ you can do /os lb edit [ID] texture [texture URL] to give ita texture

to be honest anything is possible with the power of code (at least virtually)

This is probably already possible without plugins, just maybe in a slightly different way. You can use things like weird min/max values to create some interesting stuff.

 - Credit to Username1274