I absolutely agree here. I do car audio professionally and work with fiberglass quite a bit. Between making the molds, the materials, etc. You will probably spend $400-$500 just to make the body... not to mention the time... it's not very feasable to do this just to make one body... now if you are going to reuse the molds and make a lot of them, then I could probably see the justification..
quick tutorial though...
Materials:
1 Gallon good tooling resin
1 Pint MEKP
8 yards 1.5 oz. chop mat
1 yard woven mat
some rope
carnuba wax
2 part expanding foam
wood (mdf perferably no less than 1/2")
a few very large pieces of 3" (or better) plastic strips at least 1/8" thick. These will be used to keep the 2 part expanding foam from expanding out of the mold...
LOTS of really cheap paintbrushes
rubber gloves
rage gold bondo
spray bondo
gelcoat
First you have to get a basic idea of how you want the mold to look... Trace the pattern and cut it out on a piece of MDF. Then cut a square about an inch larger than the pattern and staple the plastic strip completely around the larger piece of wood and screw the pattern in the center of it... NOW here is where you could possibly do this in one of 2 ways... If there are no belly cuts, arm cuts etc, you could probably just cut a few patterns with a router and staple and glue them together until they are the width that you need the pattern to be and wrap them with plastic wrap, being careful NOT to overlap because it will show up in the mold, OR you could mix some 2 part expanding foam and pour it into the form and when it expands and dries, using an electric knife or razor blades and sandpaper, cut the foam down to the desired shape... This is particularly useful if you have belly cuts or want belly cuts...
Now whichever way you chose to get your desired mold, now is the time to lay the chopmat and fiberglass to make your mold...
Liberally rub the carnuba wax over everything that you don't want the fiberglass to stick to, and believe me the only thing that it won't stick to is plastic, and cut the chop mat in to small workable squares. Now mix the fiberglass in 8 ounce portions according to the manufactures directions. Mix the glass to hot, and you could shrink it to much and cause warping of your mold, or it could become too brittle to even use, or mix it too cold and risk it taking until next Christmas to dry. Also the reason to mix it in such small portions is that you only get a few minutes of working time with the glass until it starts to set. Small portions means less waste.
Lay some mat on the mold you made and dab at it with the resin soaked paintbrush Get all the airbubbles that you can possibly get and work your way around the mold at least two times with the chop mat...Let the mold dry when you finish..
Next carefully seperate the mold after at least a day of drying time. Take some bondo and fix any imperfections in the mold and sand it smooth...
Now you should have a mold of the piece you are trying to build, so first wipe down the mold liberally with the carnuba wax or mold release agent, and lay in evenly the woven mat and soak completely with resin... Let it dry. Once dry, lay in some rope to add strength to the structure and resin in sqaures of chop mat over the rope and the dried first layer... add at least 5 layers to it...7 is the perfered number... let it sit for about a week to properly cure and release it from the mold. You should now have a very nice looking fiberglass piece that you will be able to prime and paint to your liking... if you make a really smooth mold, you could also add a gelcoat color to the mold prior to putting in the woven mat and when you pull out the piece you molded it will also be the color you want to have...
As for half inch vinyl, you may want to talk to upholstery shops or just make your own...
That's all for now...
Good luck