I love Hammond die-cast aluminium boxes for single-board computers. They're relatively cheap and moddable with hand tools (anything sharp that can cut wood, can basically cut aluminium too).
What I lack is a small milling machine to mill customized lids with bosses inside for interfacing to hot chips. In other words, I like to use the boxes upside-down, with the board sitting on top of the lid (or more properly, hanging off the lid, right way up). Before milling one from aluminium stock, I do recommend 3D printing one first (with low infill, for speed). I have almost a dozen different Linux SBCs, mostly older cheaper ones.
I've looked at Proxxon mills (MF 70, FF 230, FF 500/BL), but as I currently live in a flat without suitable shop/workspace, this is on hold for now.