Interesting idea, but it would be an absolute nightmare to administer - each thread would have to be closed individually and finding them in time could be a hit and miss event.
Also, given my experience of other fanworks auctions, staggering it could give some people an unfair advantage. There always seems to be someone, or a few someones, who apparently has unlimited resources and is bidding aggressively on multiple items. A standard close time means that person can only seriously watch one or two items at the end time - staggered times could mean they could bid out everyone else on multiple things.
Wendy
