I just thought about adding this to my addon FCOGuildInfo but then I talked to a dev who should know and he told me:
Code:
there is no way to get the item info outside of guild stores and you have to switch to each guild in the code in order to query it
So getting the listed items for their count, the information and the price it's listed for, needs a lot of work, event checks for new listed/aborted list etc., cache them in the savedvars for each char and update them properly each time.
So I'm not adding it as it is too much work, and would blow up the savedvars of the addon, sorry.