Keith Davies has a great post on card-based looting, written in reponse to a Google+ comment of mine. My basic concern is that I want some quick and easy rules for how long looting a place takes and how much can easily be hauled away, particularly when the scenario involves some sort of time constraint. Does the party grab whatever is handy? Do they focus on the obvious high-ticket items or poke around for concealed treasure? If the player says "I dump my pack and quickly refill it with whatever I can grab" then what ends up in their pack?
The latter case I thought quite a deal about for the Caves of Myrddin expeditions. There was a reasonable chance that the dragon's hoard could be found while the beast was away, but it could come back suddenly. I actually worked out ahead of time the proportion of silver to gold to platinum that a hastily filled pack would yield. A spreadsheet could make that an easy task for any big treasure pile: plug in the numbers and Bob's your uncle.
Keith's deck-based solution sounds fun, though filling out a bunch of index cards ahead of time would be a bit of a chore. And I kinda like the idea of having a big ol' stack of cards that I would break out for special occasions.