We're working on a post-quantum sig scheme, hash-based, that we hope to submit to NIST. Code name: Gravity. May or may not rely on B2b and https://github.com/veorq/blabla. The hardest part is to design something simple enough yet fast and stateless. SPHINCS is fast and stateless but incomprehensible. Goldreich is stateless and simpler but inefficient. Looking for a middle ground.