Dang, Jeff. This thread is so cool it just brought me out of retirement!
And being really old and into this stuff for many
o) years, I'd be remiss if I didn't mention the classic, rock-opera innovators such as The Who, Meatloaf, the Doors, and the Jefferson Starship. It's not 'metal', and it may not be what you're looking for...but it's fun. Here is a link to one of my favorite classics. Much good cheer to you! RJ
Oh yeah, and just for the hell of it, here is some totally-fun-classical gas-pseudo-rock!
I hope it's not too OT, but he's one of my favorite musicians.