fiberglassing under rear shelf /trunklid?

I consulted with a local shop today and they told me i had to build a REMOVABLE mold of some sort if i want him to make the piece for me. I have no idea how to do this, he also said it needed to be fairly defect free. I guess he just wants to put a gel coat on it, then some glass then be done.

 I had planned to do this myself, but after looking at the price of good resin and materials and considering the fact that i want a show quality finish, i thought i would check with this shop. He said he would do it but i needed to build the mold. How can i do this? Or should i just do it myself? I am very skilled and have alot of tools, i am just not into body work, nor do i know much about fiberglass.

I am also installing a 15" flat panel in my trunk lid and want to make a glass cover to go around it and to house 2 speakers. Guy told me same thing, basically get a junk lid, make a mold of some sort, then bring it to him and he will make the cover for me. What do you guys think? How should i go about this one too?

what about installing your ps2 into your rear deck so it can be accessed from inside the cab area and make a fiberglass cover just as you are for your deck lid? i do body work and have some experience with fiber glass, it's messy and boy does it give off some fumes.here is a few things you might consider useing in the construction of your cover moldings and like i said "some experience", light chiken wire ( for shaping ), stretchy polyester material for resin to bond to and make a smooth surface, body filler for your final finish, and of course sand paper 80, 150, 320 grit. since i plane on doing some similar work i'll keep you posted if i have any ideas or problems in the process.