Yes, it's possible. You need a ballast, wiring and connectors (normally supplied with ballast) and a bulb. Many times you can purchase all the components as a kit.
Regarding the how to part. Do a CPF Only Google search at the upper right and type in HID conversion. Also, scroll down the main page here and see what kind of conversion chat is happening.
I don't know of anyone who has performed the conversion on a Litebox specifically but the principle is the same for all of them. I'm not sure what Automotive equivalent bulb type the stock HID Litebox is using but you can call Streamlight and ask.
Regarding used lights, have a look or perform a search over in the
CPF Marketplace.