This should probably not be in the addons and UI mods forums as addons can not be installed on consoles, but instead in the feedback/feature request forums (if there is one, I cant seem to find it).

The reason why I believe this will not be implemented ever - the entire purpose for having the guild traders and not a central market is so that if people want to have the best deal on something, they should have to go and look for it. At least that is my opinion on why it won't happen. If zos didn't intend for this, they would probably have added a central market of some sort, like plenty of other MMOs.

As for something that is present right now, there's an addon and website called Tamriel Trade Center, that provides similar information to what you requested. However, this is a community-based website, so the information is almost always slightly out of date.