Someone is now selling a reproduction of the Blockbuster carrying case for the Virtual Boy. The case is made-to-order and comes fully assembled; No cutting of the inner foam required: https://www.deviantart.com/virtualboyshop
It’s very expensive at $185, but the creator’s goal was to make it the best way to protect your VB. From the page:
These cases are manufactured from prime, high-density polyethylene, with double wall construction. The textured exteriors resist dents, cracking and scuffs. The shells are unaffected by extreme temperatures. The hardware features mechanical latches that are field replaceable, and a mechanical hinge system that is made to last. All cases meet U.S. 94B Specifications as an electrical insulator and are impervious to chemical attack. Polyethylene foam is resilient, closed-cell foam ideally suited as the material or a component material required for shock absorption and vibration dampening. Additionally, it functions as insulation, buoyancy and barrier components and as cushioning material in packaging.
The same seller also offers other cases, including one dedicated to just VB cartridges for $100 and some for the Vectrex as well (not pictured on their page).