Less a suggestion and more of an ease of use change... There is no point to having BoP items list in the Shopping - Quick Posting window. We can't sell them, there won't ever be any on the AH to search for... why have em listed? just makes it harder for you to spot the items you are looking for, especially since the list seems to have absolutely no sorting whatsoever.
edit: now I also have a suggestion... a way to post after searching with Shopping - Quick Posting, when there aren't any search results. All it would take is allowing us to click the Post button without a selection, and have it come up with all zeros in the boxes... =-) Just a lot easier to use the quick post then to have to change to the default AH tab and do everything manually.
And also... sort the Quick Posting window Alphabetically... =-) or in bag order, or something. Some sort of sorting.
So looking at the coding, it already appears that it should be filtering out Soulbound items... but mine is most certainly not. The code in UpdatePostFrame shouldn't even add the item to the list if tsm:IsSoulbound is true, so that must not be returning properly.