Hi Lauszus.
I must admit I wasn't able to understand all the details you posted but I found your mini balancing robot very interesting. Great job!
I was also looking for 10 inch wheels and your video solved the issue (with www.northerntool.com).
The 6 dof Imu on sparkfun has been "retired" and I could not find it on watterott.com either. I guess I will stick with the tinker-arduino version hoping it will work....
I will probably be back with further questions once I have studied your Imu link.
Ciao.
Roberto