I've heard various methods of getting dents out, but have never tried any so I can't give you personal info. However...
- suction cups
- drill a hole, get a hook, pull it out, fill with Bondo
- dry ice
-I'm not sure how you could do this with an entire hood.
Those are the only ones I can think of off the top of my head.
Hopefully someone else can elaborate or post other methods they have heard or tried. Best of luck.