(note, this isn't necessarily something for DoD but for modeling for HL in general)

http://sonic128.tdekon.com/storage/lolaser01.jpg
http://sonic128.tdekon.com/storage/lolaser02.jpg
http://sonic128.tdekon.com/storage/lolaser03.jpg

a light saber that actually looks decent in the HL engine. and as you can see, its aesthically not that great looking. but techically i think its as good of a light saber you can get in HL.

all i did was create a cylinder with a rounded tip, then inversed the faces(kind of how you would do "black lines" on a cell shaded model), of course applying a texture to it, and compiling the blade texture in additive transparency.

i think with a little more experimentation its possible to make a really authentic looking lightsaber in HL.

That actually looks pretty neat.

Except that it doesn't glow in the dark. Like any other model, it turns black in shadows.

i will respond with my new favorite answer

just wait for HL2