Back to the future on Wall Street? Wunsch Auction Systems aims to re-create an old-fashioned stock market -- no dealers, no brokers, just buyers and sellers trading at the same price, same place, same time -- but through a new electronic exchange. Launched in April by former broker R. Steven Wunsch, it hosts off-hours auctions 10 times a week, allowing buyers and sellers to place orders directly by computer, eliminating the middlemen's high commissions. Wunsch's exchange charges a penny-per-share fee, compared with the 6¢ to 16¢ investors might pay brokers. Currently restricted to institutional investors, the exchange already deals in 3,000 stocks, and an average day's volume is 120,000 shares.