I have spent some time figuring out how best to tackle these kinds of characters in Maya.
So here are a couple of characters which you may recognise from all the recent drawings depicted in 3D:
I wish I could say I have 50 or so 3D characters to show, but it has taken a bit of time to get this far as I have put plenty of thought into the way they are created. (in the hope that making more will become quicker and easier as I figure out the best workflow)
In terms of making masses of background characters, I'm thinking that we could do this in a modular fashion. Many of the designs are reusing bits of musical notation in different ways, and I think we can use this to our advantage to create reusable bits of characters.
Anyway, let me know if I'm on the right lines or not. I think I want to have a go at more making more characters from the designs we already have before I start delving into rigs.