I'm going to have to say if they did that it would be a MASSIVE pain in the butt to search for the item you wanted in the wards. Using your same example of the Decorated silver scepter, lets say for simplicities sake that they did 5 tiers of stats (every 20 Quality) on TOP of the three HQ tiers... now SE would either have to add every possibility under the search menu, or you would have to run your butt into every ward that its listed in to check, one by one each seller to see if they have the one you wanted. Then you have HUNDREDS of people that can make it, selling every tier, where you have to sift through them ALL.

A simpler idea would be just to have the HQ's have a tiny bit of a buff to the item in some way and the wards (when your using the search function) to have maybe the listed HQ's in a different colour.