A DEP B737-200 HAS A FAILURE OF THE BLEED DUCT IN THE FORWARD CARGO BIN IMMEDIATELY AFTER A 'BLEEDS OFF' TKOF FROM PVD; RI. FLT DIVERTED TO BOS FOR LONGER RWY AVAILABILITY.

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JUST AFTER TKOF FROM PVD (TF GREEN STATE ARPT; PROVIDENCE; RI) WE HEARD A LOUD MUFFLED SOUND FOLLOWED BY A SURGE IN CABIN AIR PRESSURE (I HAD RECONFIGURED THE BLEED AIR PANEL PASSING 400 FT -- WE HAD DONE A BLEEDS OFF TKOF DUE TO WT AND RWY LENGTH CONSIDERATIONS). SHORTLY THEREAFTER THE FLT ATTENDANT CALLED TO SAY THAT SHE SMELLED SMOKE AND THE CABIN BEGAN TO FILL WITH SMOKE. WE FOLLOWED SMOKE IDENT/REMOVAL PROCS AND DONNED OXYGEN MASKS. AN EMER WAS DECLARED AND WE PROCEEDED TO DIVERT TO BOS DUE TO THE LONGER RWYS THERE. THE FLT ATTENDANT SAID THAT THE SMOKE SIT HAD IMPROVED (WE HAD DEPRESSURIZED THE ACFT PER PROC). I INFORMED THE COMPANY OF OUR PLANS VIA ACARS AND VHF RADIO AND PERFORMED ALL REQUIRED CHKLISTS. AROUND THIS TIME THE FLT ATTENDANT SAID THAT THE FLOOR UNDER THE R SIDE EXIT ROW WAS EXTREMELY HOT. I IMMEDIATELY SHUT OFF ALL BLEED AIR AND BOTH PACKS. THIS SEEMED TO HELP. WE LANDED UNEVENTFULLY IN BOS AND WERE MET BY BOS ARFF CREWS WHO CHKED US OUT ON THE RWY (22L) AND SAID THAT WE APPEARED TO BE OKAY WITH NO VISIBLE SMOKE. THEY HAD USED THIS NEW THERMAL IMAGING DEVICE TO DETECT HOTSPOTS. I DECIDED TO NOT DO A GND EVAC AND TAXIED THE ACFT TO THE GATE WHERE WE WERE MET BY MAINT PERSONNEL; COMPANY OFFICIALS; FAA INSPECTORS; INFLT SUPVRS; GATE AGENTS AND MEMBERS OF THE BOSTON ARPT FIRE DEPT. THE ACFT WAS OFF-LOADED UNEVENTFULLY AND WITHOUT PANIC. DURING THE POSTFLT INSPECTION IT WAS DETERMINED THAT A BLEED AIR DUCT BEHIND A PANEL IN THE FORWARD CARGO BIN HAD BLOWN; SENDING HOT BLEED AIR (MOST LIKELY 13TH STAGE HIGH PRESSURE -- VERY HOT) INTO THE SPACE UNDER THE R OVERWING EXIT ROW CAUSING THE SMOKE AND FUMES. ALL APPROPRIATE COMPANY OFFICIALS WERE NOTIFIED AND A LOGBOOK ENTRY WAS MADE FOR THE OVERWT LNDG. SUPPLEMENTAL INFO FROM ACN 467456: CHKLIST CALLED FOR LEAVING BLEEDS ON. IT WAS VERY NOISY MID-CABIN. BLEEDS WERE TURNED OFF AND FLOOR TEMP SUBSIDED. COCKPIT CREW DID NOT DETECT SMOKE AT ANY TIME; BUT DID DETECT A 'HOT' SMELL. OXYGEN MASKS WERE DONNED; BUT SMOKE GOGGLES WERE NOT.