youre looking at LOTS of money. most those "custom" cars are owned by the shops, so its a freebie cause its their show cars. or the owners get a hookup, or theyre rich.
man i love fiberglassing, but a whole dash, goddamn, i dont even want to think about the amount of time that it would take. i can see if you wanted to add a few things like maybe a speaker pod for tweets up in the dash, or a pod for gauges over the center console.
wrapping it in vinyl/leather/tweed isnt that hard, just gotta have finesse. i wouldnt recomment a smooth glossy finish, that will kill the eyes.
what exactly are you looking to do, full dash, add ons?