But it's hard to find and get started with a good open source toolchain. I have heard good things about IceStorm, but haven't gotten around to setting it up.
It's great and inspiring to see people successfully stepping through these sorts of starter projects and documenting them, though!
That's because there aren't any. The one you have happens to be the exception - it's the only FPGA line with an open source toolchain AFAIK. FPGAs are the realm of large, heavily proprietary build environments.
Incorrect. See: http://www.clifford.at/icestorm/
If you meant more how to get involved with the community effort, I'd start with Clifford Wolf's page (http://www.clifford.at/icestorm/ ). He's the main guy behind the efforts with the iCE40 toolchain and his page links to some other efforts to reverse engineer Xilinx and Altera chips. There's a lot of interest in more open FPGAs, but I think there's a lack of skilled people so you'd likely be welcome.