Differant types of merchants

I think Guild Wars should make more merchants such as:

Green Merchant: Only accepts greens and pays about half of what the green is worth

Gold Merchant: Pays like 1k per item...more for good items with more mods

Purple Merchant: 800g per item...More for better mods

Blue Merchant: 30g per item...More if better mods

Also a Merchant That Buys Mods For Half Of What There Worth

I think they already started that with the "Material Trader" and "Rare Material Trader." There are also multi-level armor crafters.

The precedent has been set, taking it a step further would be great.