A reverse auction is where the more people that bid on an item, the more the cost comes down. I recall letsbuyit.com being a reverse auction site during the e-boom a few years back. Effectively they would do a deal with a TV manufacturer, say, whereby if they got 10 orders they could have each TV for $200 but if they got 40 the price would come down to $170 each. Hopefully that answers your question draftech.
Re your question wickes, Ebay does not do 'reverse auctions'. Besides, there would be no point in hiding your bid until the last minute as the earlier it was placed, the sooner other bidders would know that there were others interested - more interest equals lower price.
Did you mean 'reserve auctions'? If yes, then AS does work for them. The only thing to watch out for is that if you bid higher than the reserve price when it is not currently met, Ebay will jump your bid up to the reserve price as opposed to putting a bid at the next increment. This is not AS's fault but just the way Ebay works. However, it has caught a few people out in the past judging by previous posts.