I spotted this machined Surefire X300 protector bezel on PPTW’s Facebook page, earlier. Same principle as the Maglite cap method, but in aluminium and shaped like the X300’s crenelated bezel itself.
It’s a really stylish way to capture a sacrificial lens, which will no doubt be plagiarised rather promptly.
More pics on PPTW’s blog.
They also do a very nice Steamlight one.