This is a concept I started working on last offseason. The result before build season caught up with me was a single speed drive with the wheel having an internal ring gear and pinions on the CIM motors directly driving the ring gear/wheel. The encoder is also driven by the ring gear through an idler gear.
The benefits ended up being a pretty significant gain in real estate on the chassis. This also resulted in some (albeit minor) weight savings compared to a standard single speed skid steer drive.*
I'll have gearing info, weights, etc. and more info posted once I can get the model open again. Comment any questions, etc. and I'll answer as I know it's tough to make everything out from this picture.
EDIT: The ring gear on the wheel is 72T while the pinions on the CIMs are 11T/12T. The encoder gear is 28T
We make ourselves better by lifting others and standing on their shoulders, not by knocking them down. - Taylor [more] 
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