Wot like this?www.instructables.com/id/Cheapy-Laser-Lighter-Burner/ L
Wow! I completely misread the question. I wonder how that happened.
Maybe I did? L
No, I think you're right. The related stuff makes me think that. There is even an instructable for "turning a lighter into a high powered laser". Ah, but we'll never know, he just joined and this is his first question so we will probably never hear from him again. And we won't get to teach him about all the great stuff on the site.
Smaller batteries. Take it out of the case. Attach a helium balloon (might work, depends on why you want to make it lighter).
Take a laser and remove all of the heavy parts.