BE76 instructor pilot reports failure of the nose gear to extend at the end of a training flight. After multiple attempts to get the nose gear down the aircraft is landed with the nose gear retracted and the engines feathered.

Narrative

After doing slow flight in the landing configuration; and shooting a LOC approach and an ILS; it was time to call it a day; as I had a meeting scheduled. Reaching the FAF; the student lowered the landing gear handle and set 10 degrees flaps. The student waited about 20 seconds and stated only two green; and the gear in transition light was still illuminated. I called Tower; and told them we have a problem; we were going to the practice area to sort it out; and would get back to them. We flew to the practice area; pulled out the checklist; and ran through it item by item. We recycled the gear at least 10 times; did emergency gear extension checklist at least 10 times; still no nose gear light. I had another instructor from our school fly under us. He stated that the left nose gear door was 'ajar'. The right was completely closed. I tried rudder to get the gear to drop; dive and pull up; steep turns and pull up. Anything and everything I remembered from hangar talk I tried. After the checklist I did two Tower fly-bys; and unfortunately both times I was told the nose gear was not visible. I decided it was getting dark; and did not want to attempt any heroics in the dark. I asked Tower to roll out the trucks (fire equipment); and that I was coming in on the longest runway. Seat belts secure; passenger briefing as to what I was going to do; and checklist. On short final; I feathered props; pulled mixture; and held the nose off as long as I could. The props feathered; and I still held the nose off as long as it would stay. The aircraft touched down on the mains; without any prop strike; and skidded about 200-300 FT on the main gears and the fiberglass nose. When the aircraft came to rest I announced 'evacuate' and all persons on board left the aircraft. No injuries; no major damage. A textbook gear up landing!