I'll be sticking to beakies for my own forces. A friend of mine is going to be doing Red Scorpions in mk 4 using the new Horus Heresy plastics and another friend is working on Marines Errant in mk 7. Another yet is doing Lamenters in beakie.
Hopefully our forces will be coming together soon. The project will start out small and work up to bigger battles. We're hoping to do fleet battles using Battlefleet Gothic too but that's going to take a lot longer.