The purpose of this concept would be to minimize the appearance of captcha, which has improved tremendously, yet is still a mechanic that makes restocking Merchant Shops tedious. It would also make buying food an easier process, especially for players that prefer to buy in bulk.

I believe Lioden and FR have this mechanic, where you can pick out the items and once you want to purchase, you can just fill out the captcha for all of them. 

No support, not right now.

Shop stock refreshes every 10 minutes, so it'd have to take into account that and if players buy out an item before you are able to. With the current shoo revamp, I can't see something like this happening for a while.