Lattice iCE40 is documented [1] and it has fully open source development tools [2], [3]

[1] https://github.com/cliffordwolf/icestorm

[2] http://www.clifford.at/yosys/

[3] https://github.com/cseed/arachne-pnr

fpgatools is a project for reversing the Xilinx Spartan family FPGAs. https://github.com/Wolfgang-Spraul/fpgatools

Do a Spartan-6 and a Virtex-6. Use the tools I linked to in my main comment where possible. Would be very useful given their price, performance, and lots of info on them.