Mellow has assembled a pendant for the Millennium Machine, Milo V1.5 works with the Fly CDYV3 and the BTT Scylla motherboards.
Milo Pendant
They've done a nice job of making a single circuit board from all the components needed in this mod and flashed the Arduino with the pendant software.
I will change the cabling to the Scylla motherboard and add a strain relief to the pendant case. They could have made a better effort in that aspect. I'll also confirm the wiring to the Scylla I/O connector when I receive the pendant.