Lendia Inc., a Massachusetts provider of mortgage outsourced services, is about to snag a client that can bring an estimated $4 billion in new business over the next few years. Greg O’Connor, Lendia’s chief operating officer, declined to identify the big client but said the profit from the partnership will help meet his company’s 36-month goal of $8 billion, beginning in 2006. He estimates that the client will be bringing in at least $1…