What about a neon tube with the external glass shaped as a blade, and made in thick tempered glass ? ..... (with cutting edges and sharp tip, ofcourse .....

)
What about when it breaks? You couldn't pick it up because you'd get zapped...right? That would suck hardcore
Or...since you want 'cutting' maybe a portable Oxi-acetalyne torch, with the proper amount of oxygen, it'll look like a lightsaber lol, granted it's only be like 18-24in long if you're lucky, it would seriously do some damage. I still have the scar on my chest because I had a bad habit of tapping the extra rod that I would use for welding, I would tap the back of it against my chest so I could weld some more (so I had something other than fingertips to weld with) well one day I accidently tapped the molten side against my chest...Burnt through my sweater, shirt, and about a half inch of flesh in only like .5sec. I didn't realize what I had done, I just thought I burnt a little bit, not through my chest, so afterwords I felt it, and essentialy...it felt like a 3rd nipple, rofl, that joke never gets old ammoung us...anyway, went to the bathroom to look in the mirror, sure enough, cauldorizerd (sp) a half inch hole in my chest. It was pretty bad ass, back when I first did it, I kept working through the pain because all I thought I did was a quick burn. Didn't bleed because it was caulderized, but it still burnt/stung like a mutha *****....Well, yeah, so now how dangerous do you think the actual flame is? The blue oxy flame is the worst, it would boil our metal on contact.
You're talking about a neon sign attached to a handle. This thread is mostly talking about a light saber that can stab you

lol
Well fine, get the following:
1x Sword..................about $120
1x Flashlight.......................$2.99
1x Roll of duck tape.............$0.99
Uncontrolable amounts of sarcasm? PRICELESS.