I'm not worried about the lack of multiblock furnace. I'm planning on including Thaumcraft and Astral Sorcery, so the Infernal Furnace will be a possibility, and I'm actually giving the player the opportunity to use IE's External Heater and not have it immediately useless. While it requires a bit more coordination to fully automate multiple furnaces using it, the results should be fairly comparable. It ends up an effective multiblock structure which smelts pretty darn rapidly (remember, the heater speeds up the smelting speed per furnace, so each furnace adjacent is going to be individually faster, plus you have multiple furnaces running independently).It's not Engineer's Toolbox. (Which made me really sad.) It's making your own multi-blocks to fill holes in existing structures. Such as the Multi-block smeltery IE lacks before you get to the arc furnace.
I'm going to start working on BWM and see if I can do it this way first. Looking over Modular Machinery, it doesn't really have what I'm looking for here for this particular pack. I'm going for a Medium-core 'vanilla++' style approach, with a steampunk vibe. Modular Machinery doesn't really give any value added to that.
I like Geolosys, I really do, and I really want to use it. But I don't think that's going to be possible. It doesn't play well with Quark's 'realistic' generation, and the json file is fairly minimal with respect to how it can be manipulated. Shame, really.