This plugin allows you to change the content of the item, hero and sprite submenu of the variable command at runtime. With a simple comment command, you'll be able to select dynamically for these instead.
for example, "@item_once 4" will change the item used for the next variable operation to be that of id 4 in the database.
A more detailed instruction is given in the readme of the download
I'm gonna mix this with KazString and have an item storage thing wholly on numbers. With that, I can have the name and amount of all items done by just four variables (and just one being changed).