I had a broken tail light and no luck finding a good one at a junk yard. Decided to fix it by making a new lens. I ran across this and ran with it. http://www.6gc.net/howto/make_clear_tail_lights It's illegal to have clear lenses and also illegal to have colored tail light bulbs. Heres how I did it but with patience you could make it look good.
Step 1: Materials and Tools
Materials Needed are: Office Lighting Covers I got a 2X4 piece at home depot. It's brittle so be careful. Something like this http://www.lowes.com/pd_227470-1390-DL2100_4294935637_?productId=1063037&Ntt=diffuser&Ntk=i_products&pl=1¤tURL=/pl_Lighting%2B_4294935637__s?Ntk=i_products$pageNumber=1$rpp=15$No=60$Ntt=diffuser$currentPage=5$totalPages=5
You are going to need glue some sort of liquid nails use clear glue I didn't....
Sand paper, Paint(rattle can), Red Glass Paint.
Tools: Dremel with diamond Cut tip. http://www.harborfreight.com/5-piece-diamond-mini-cutting-discs-31501.html
Step 2: Breaking and Painting
Now pry the old lens off, paint the inside with chrome spray real well but tape off the section your going glue so that it sticks to the plastic and not the paint.
Cut out with dremel tool and diamond bit approximately how much light diffuser you'll need if you have a corner to bend around use the soldering iron on top to melt through it enough that it will bend around the corner but not break and not leave a hole.
Put the glue all around the outside of the plastic casing and stick on the light diffuser. clamp it down using whatever and let it dry.
Step 3: Cutting It Precisely.
Now that it's glued on firmly use the dremel to cut precisely around the plastic or if the previous lens extended then cut it to the old lens dimensions. Then if your like me and would like to not get pulled over paint the brake light with the red glass paint and the turn signal with yellow or use a amber bulb for the turn signals. Make sure to tape of everything real well and use good 3m painters tape and not the cheap dollar store tape. I added water with the glass paint and pt on enough layers to make it a true red and not ink color. Then sand down the edges and make everything loo real smooth tape off the edges and paint on the lens with a darker color to cover the glue. Make whatever else designs you want.
Step 4: Finally.
I put a gloss coat over the entire thing at the end and I think it made it look a lot nicer. put everything back together and see how it looks. mine looks a little cheesy but works well and looks better than having tape or just a broke open turn signal but if you take your time this could look nice. It doesn't really bend so if your tail lights have a lot of curves not sure how well this will work. Here it is basically finished i didn't have it screwed in so it looks a little buldgy in this picture.