OUTLINE: This is a two part, radiation dose escalation study. Peripheral blood stem cells (PBSC) are collected after 5-6 daily injections of G-CSF. The PBSC are infused in two halves. One half is given after chemotherapy and the other half after total marrow irradiation (TMI). Transplant #1 (part one) consists of chemotherapy and PBSC infusion. Busulfan (BU) is administered orally every 6 hours for 3 days for a total of 12 doses on days -8, -7 and -6. Melphalan is intravenously infused over 30 minutes for 2 days on days -5 and -4. Thiotepa is intravenously infused over 2 hours on days -3 and -2. PBSC are infused on day 0, 36-48 hours after completion of chemotherapy. Patients are considered for local irradiation therapy between transplant #1 and #2 if tissue limiting irradiation doses to bulk tumor site have not previously been administered. The local irradiation is given immediately prior to TMI administration. Transplant #2 starts sometime between day 60 and 120 after transplant #1. For transplant #2, cohorts of 4 patients are treated with TMI twice a day for 5 days at initial dose level on days -5 through -1. TMI is administered over 30-40 minutes. The second half of the PBSC is infused 1-24 hours following the last dose of TMI. After treatment of at least 4 patients at the initial TMI dose level, dose levels escalate in the absence of toxicity. If there is no dose limiting toxicity (DLT) in the current group of 4 patients, the next cohort is treated at the next higher dose level. If 1 of the 4 patients experiences DLT, the next cohort is treated at the same dose. If 1 DLT is seen among 8 patients treated at a dose, then the next cohort is treated at the next higher dose level. If 2 patients out of 8 experience DLT, this dose is identified as the maximum tolerated dose (MTD). If 1 out of 4 or 3 out 8 patients experience DLT at a dose level, the next lower dose level is identified as the MTD. Each patient in a cohort is observed for a minimum of 28 days prior to escalation to the higher dose level. Tumor restaging occurs approximately 9 months after initial transplant, then at 12 months and annually thereafter.