Setting prices shouldn't be that hard tough. You could ripoff the merchant frame and make it so you can put items "in it" from your bags and set a price, as easy as that!
Tons of ways to do this, thing is, is it worth it to go this deep into a project like this? Hmm... something that requires others to use the same addon in order to work is nice but usually small time addons have the big problem of starting up. I think people are so into the AH game by now that it may be hard to get noticed with a new concept like this.
