My VendorMaster addon will do that as well, though it is after the fact.
Addons don't know how much it will cost you to repair until you visit the repair vendor (unless they kept a large database and did a bunch of math).
This plugin will display the value of the junk in your inventory.
http://www.wowinterface.com/download...r_Garbage.html
There are other LDB displays to show your durability status.