I had actually planned on integrating a grading system into my website once we are hatching/selling little ones. I was going to use a similar scale to
http://www.fireandicedragons.com/pricing.cfm which is this (Note, this would be a general guideline, as working with bp's you don't have the vast numbers that dragons produce.):
How we generally rank quality:
1. Pet Quality - The 2 or 3 dragons in each clutch with the least amount of color. These are available at a low cost and show more color than pet store dragons.
2. Breeder Quality - These dragons are average in color for the clutch. This group is medium priced.
3. Hold Back Quality - These are intensely colored dragons; the top 2 or 3 in the whole clutch. Our breeders come from this group.
4. Collectors Quality - These are the best of the best. Maybe 1 dragon per clutch. Our breeders come from this group.
Obviously I will need to tweek it, as I see how things pan out over the years. But it's a start! I think it would be practically impossible to have a "standard" among the community, as has been stated, because of the opinions varying so much on certain traits.