[BJC]

Going back to the problem before the answer thing. What do you want out of you drivetrain? It sounds like you currently just want it to be different then normal?

I would suggest looking at things that could be improved within your current drivetrain.

How to increase your robots tractive force?

How to make your robot more manuverable? (strafing or just turning)

How to make it weigh less?

How to make it more easily repairable?

How to get your CoG lower?

How to get up an incline?

How to make it able to stand its ground when hit from the side?

Ect.

So if your robot needs to be a triangle to better do some of these, then you should make it a triangle.
Because I gurantee you that if you can do some of these things, even if they arn't visible at first glance, you will have a more competitive robot and people will notice the difference.