RATIONALE: Drugs used in chemotherapy, such as busulfan, etoposide, and cyclophosphamide, work in different ways to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Giving colony-stimulating factors, such as G-CSF, monoclonal antibodies, such as rituximab, or chemotherapy, such as etoposide, helps stem cells move from the bone marrow to the blood so they can be collected and stored until transplant. Giving etoposide and G-CSF together with rituximab before a peripheral stem cell transplant may be an effective treatment for non-Hodgkin's lymphoma.