TUCSON, Ariz. -- A weekend sampling of stores in this sun-dappled city found that area Wal-Marts still use conventional 25- or 27-inch monitors to broadcast its Wal-Mart Network. However, digital menu-board signs are installed in at a least one McDonald's. Smaller, digitally controlled flat panels are cropping up in hotels and banks.
Arizona's second city is a fine laboratory for supermarket watchers. Safeway, Albertsons, Wal-Mart supercenters, Kroger's Fry's division and locally owne