6D Mag torch...that is one big torch!
Most of the torches you mention have been modified to use Luxeon's!
The easiest mods you can do on these is to fit a drop-in PR Based LED bulb; these are available from LED Tronics Inc; this allows you to revert back to filament operation should you really want to.
You can of course modify PR Bulbs yourself using discrete LED's and resistors.
If you want to modify your torches to Luxeon LED operation, there are plenty of torchaholics who will help you in your quest; Electrolumens and Lambda have got plenty of examples of Luxeon modified Mags, including the Hydra XP4, presently the planet's brightest LED torch.
It would be interesting for someone to come up with a mod for that huge 6D mag! This is definitely not the torch for the shy reclusive torchaholic! Maybe 5 Luxeons, or a 4 * 5W Luxeon torch! In a 6D, you have 9 volts and a lot of Ampere-hours to draw upon, so it's worth making a mod which will gfive you some serious illuminating power, particularly as the torch is so heavy and battery hungry!