We all know how closely lenders keep tabs on lendees that show any signs of failing health. But it may not be a bad idea for lendees to do some checking of their own, now that bank failures have become a routine news story. For $2.40 a copy, the Federal Deposit Insurance Corp. will send out quarterly "call reports" on any of its 14,000 member banks. Although the reports offer no rankings or editorial comments, they contain enough financial data for an astute reader to detect early warning signs of trouble. It may be time to take your business elsewhere.