If an old bike is mostly toast, then rat away! I love custom anything! What Frank did is a textbook example. If it's close enough to original, and clean enough to ride as-is, then ride as-is. If it needs a restore, and you're willing to go the distance on the project then restore. I for one, love seeing the better-than-original restorations with professional paint jobs, new chrome, reupholstered saddle and the works.
The only thing in this hobby that burns me up is seeing a beautiful survivor, a bike in good shape that's got all the original parts, get parted out for profit. To me, that displays a craven, crass, and mercenary lack of values. It destroys a piece of Americana for the sake of a few bucks in someone's pocket. There is an example or two in the sales section right now. And, just so I'm clear- I have no objection to parting out some frankenbike, or a bike that's mostly stripped to begin with, or one that is missing so much stuff that it's not worth a restoration.
JWM