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.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.