I want to use Mir BFT instead of Raft, which is not fit for our slightly more secure purpose. However it appears that Raft is quite embedded in the code.
Has this been attempted/is it in the pipeline/should I just be using sawtooth instead and leave Fabric alone?
Mir BFT isn't implemented in Fabric just yet. It's future work.
There is, however, an integration of another BFT library in Fabric which is not an official Hyperledger effort.
The integration is based on Fabric v1.4 and is publicly available on dockerhub.
The paper of the project can be found here.
If you look at the commits in the branches of release-1.4-BFT-*, you'll see roughly what things you need to do in order to integrate another consensus library in Fabric.
Also you can look at this RFC and the comments within.
