Henrik Forstén built a board with an Atmel ARM processor in 217-ball BGA package using OSH Park and OSH Stencil:
I wanted to try designing a board with BGA chips in it to see how hard soldering them could be. So I decided to design a small ARM embedded system that can run Linux. ARM processor that I decided to use was AT91SAM9N12 in a 217 ball LFBGA package, just because it was the cheapest ARM processor with memory management unit which is required to run Linux.
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.