Finally built myself a nice 3D printer enclosure from IKEA cabinets.
Basic idea is to take a shallow (20cm) and a deep (40cm) cabinet frames and to stagger the bottom/top panels and wall panels, making a nice single-piece 60cm cube. A bit more info with a short how-to and a few ideas and nuances.
The issue I have with the enclosures I see that most people design for themselves is the complete lack of ability to have easy access for maintenance and repairs.
It's can be a royal pain in the butt to pull your printer out to do simple tasks for maintenance so you put things off until you end up have bigger problems that are harder and more expensive to fix.