How to design a Spartan-6 PCB?
The Spartan-6 LX9 is available in the hand-soldering-friendly TQG144 package ([UG385] v2.3 at p. 30). Numato designed an open-hardware board around this FPGA/packaging: the Mimas Spartan-6 devel. board [NUM1]. The KiCAD  schematics and PCB layout files are found in Numato's SVN repository at [NUM2]. In addition, Numato created a component description file for this packaging: XC6SLX9-2TQG144C.
Numato's Mimas PCB
Other examples of a Spartan-6 PCB design
Chris McClelland also made his own Spartan-6 development board as open-hardware there: .
How to design a STM32-F4 PCB?
The STM32-F4 was chosen for bit-banging the configuration of the Spartan-6 FPGA. In its smallest packaging (LQFP64), a very compact board can achieved. Frank Zhao designed a bread-board-friendly breakout board for the STM32F405RG . The EAGLE  design files can be found at .
Frank Zhao's STM32F4Stamp PCB
|[UG385]||Xilinx Spartan-6 FPGA Packaging and Pinouts http://www.xilinx.com/support/documentation/user_guides/ug385.pdf|
|[NUM2]||Numato SVN repository instructions http://numato.cc/content/how-checkout-files-numatocc-svn-repository|
|||Silicon exposed blog, http://siliconexposed.blogspot.de|
|||Kevin Modzelewski's blog, http://blog.kevmod.com/2013/09/choosing-fpga-parts/|
|||Kevin Modzelewski, Spartan-6 Breakout v0.1, https://oshpark.com/shared_projects/duLs3P1R|
|||miniSpartan6+, kickstarter campaign, https://www.kickstarter.com/projects/1812459948/minispartan6-a-powerful-fpga-board-and-easy-to-use|
|||miniSpartan6+, Eagle schematics and PCB files, https://github.com/scarabhardware/miniSpartan6-plus|
|||Gadget Factory, PapilioPro, http://papilio.cc/index.php?n=Papilio.PapilioPro|
|||KiCAD official website http://www.kicad-pcb.org|
|||STMicroelectronics STM32F405RG Product page http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1577/LN1035/PF252144|
|||CadSoft EAGLE http://www.cadsoftusa.com/eagle-pcb-design-software/about-eagle/|
|||Frank Zhao's STM32F4Stamp http://eleccelerator.com/stm32f4stamp-breakout-board/|