Tampa's downtown waterfront is set to grow taller. Real estate developer Strategic Property Partners, backed by Microsoft co-founder Bill Gates' Cascade Investment LLC, filed plans this week for a new 33-story luxury residential tower at the corner of Water Street and Cumberland Avenue — the latest addition to the sprawling Water Street Tampa district. The 400-foot tower, which has not yet been named, will rise across the street from Predalina restaurant and Synovus Bank. Acc