I have been working on these for some weekends now and to my amazement I am making some progress. My github repo: GitHub - kurkesmurfer/Schlappi-vcv · GitHub
As a straight port ran into severe computational limits I have chosen to change the core quite a bit as well. I am using cheaper low pass filters to combat aliasing artefacts, and cut oversampling in favor of alternative algorithmic approaches. I must admit I am already quite happy with BTFLD, but also still trying to improve the sound quality. Cpu load has gone down enough to allow some elbow room. It is stil very much a WIP.