For the love of CIMs (A question about CIMs and gearboxes)

I love the CIM motor. I really do. However, the only thing I don't like is that you can only use 4 of them. And for the most part, most gearboxes only allow 2 inputs, still capping you out at 4 per robot.

So my questions are:

1) Have you ever been able to use more than 4 CIMs on a robot?
2) What are your thoughts on a custom gearbox with 3 CIM inputs, and one output?

The CIMs would be in a triangle formation around a central drive gear. This could allow for a smaller gear reduction, or a robot that is both faster, and more powerful in one.

And just for the fun of it:
3) What would a 4 CIM gearbox be like? What would the advantages be?