All I really need recommending are the Motherboard and CPU. Would anyone be able to recommend me some?
It depends on whether you want to make some other use of the machine as well. For a mining-only solution I'd stick with some low-cost motherboard of a reputable brand (my favorites are Asus and Gigabyte) and purchase the cheapest compatible CPU, regardless if Intel or AMD. However, I'd think of some extensibility for the future, so I'd recommend giving a go to a motherboard with 2+ PCI-E 16slots. Remember the slots shall not be adjacent to each other, so you can fit two (or more) dual-height cards.