ARM I: Patients receive rituximab IV over 30-60 minutes on days 1, 8, 15, and 22 (of courses 1 and 4 only) and bortezomib IV or SC and dexamethasone PO on days 1, 8, and 15. Treatment repeats every 28 days for 6 courses in the absence of disease progression or unacceptable toxicity.