After the announcments of Unity 5 and Unreal Engine 4 being free I lost a bit of motivation to continue with my personal engine. After a while I decided to see if I could get what I've done working in Unity to see how it fares.
It's a few steps back but I have Minecraft worlds loading using Substrate as external code (a plugin). The blocks are loaded and the mesh data prepared on a thread, and then passed to the main thread for object and mesh creation. It manages to keep a solid 60+ as well, hopefully I can add the texture loading as well without impacting it.