That's pretty nice, not entirely accurate but it's good to see the neck ring. I'd hope it wouldn't be recast; you can do better with stuff already out there.
I'd reckon all finished for about $400. Plus if you got something like an OSCS helmet it would have the accurate raised lip around the visor and a more accurate chin/vocoder area.
I'm actually looking in to that myself. There is a guy over at CTN who found some material that matches closely to what was seen BUT it's no longer available. If I find some though I'll let you know, it's got to be out there somewhere.
I think it look OK. The paint is nice but the chest appears kinda small for me. Here's some that I have build. The are all wearable costumes. The 501st version I no longer have, it was built for a friend. I got the neckseals from someone on clonetroopers.net
Darren