The easiest method is simple wet layup of CF on existing parts. I have done this extensively using epoxy resin. If you are fabricating something, then it gets very pricy as far as making just one plug of the part... the supplies for building a mold are better invested if you're planning on doing multiple plugs in some sort of production environment.
Take a look in my gallery and you can see some shots of my Kawasaki I did wet-layup on. After you polish the epoxy, it looks pretty fantastic. The only thing to be careful about with epoxy is that any moisture in the air will cause a cloudy effect in the final product... its difficult to avoid, but minimally noticable if you are careful and don't use multiple layers of resin.
Your best bet:
Build a model of what you want to install. Leave some space for buildup if you're mounting it and need a specific dimension to make it fit. typically a single layer of fiber and epoxy will build about 3/32" or more depending on how liberally you apply the resin. Next. Paint your model part black. Use flat black, and leave the surface rough so there is good adhesion. Next, mix up some resin and paint it over the surface with a brush. Let the resin tack up (toward the end of its pot life, and beyond) and then apply a sheet of fiber. it will stick easily and mold to the surface if your resin is appropriately tacky. now, ideally at this point you would have a buddy who's prepped another batch of resin for you for the final lamination. using a glasskoter brush, apply the laminating layer of resin to the entire object. obviously it is best to do this in a dust free environment. use a fast curing epoxy. if you get a good buildup you can then polish the item until you can see your reflection in it.
pm me if you have more questions. this is not an easy process, you'll ideally want lots of practice before you do something as blatantly cosmetic as a dashboard.
another factor is you'll have to UV-proof the dash... some sort of clear coat. Not really sure, I haven't made it that far.
i take it back, the photos in my gallery suck
don't go by those as what the end product of wet layup looks like. its much more attractive in person.
i'll see if i can post some better shots.