NMAC OR NEAR COLLISION ON RWY AT NON TWR ARPT UNICOM.

Narrative

OWNER/PLT DROPPED OFF ALL INSTALLED RADIOS FOR UPGRADE. AS WE TAXIED OUT TO DEPART HE ATTEMPTED TO CALL UNICOM ON HIS HANDHELD; WITH HEADSET PLUGGED INTO IT; FOR ACTIVE RWY. ALTHOUGH CHARGED AND TESTED; THE PREVIOUS NIGHT; IT DID NOT WORK. HE STOPPED TAXIING AND WE VAINLY TRIED TO TROUBLESHOOT IT. I GOT MY HANDHELD AND CALLED UNICOM FOR RADIO CHK -- OKAY. PLT DID RUNUP AT END OF RWY FACING INTO WIND; THEN DID A 180 DEG TURN IN FRONT OF HOLD-LINE TO CHK FOR TFC. WE BOTH LOOKED UP FINAL AND BOTH BASE LEGS -- NO TFC AND NONE RPTED ON UNICOM. I XMITTED WE WERE TAKING RWY 7 AND DEPARTING. AS WE ENTERED RWY AND TURNED L; AN UNANNOUNCED AIRPLANE AT MIDFIELD BEGAN TO SLOWLY CROSS THE RWY. (I NOTICED THE PLT OF MY PLANE WAS LINED UP ABOUT 8 FT TO THE L OF THE RWY CTRLINE). WE WAITED ABOUT 20 SECONDS FOR THE OTHER PLANE TO CLR THE RWY; THEN BEGAN OUR TKOF ROLL. WE WERE A FEW SECONDS BEFORE LIFTOFF WHEN A BIPLANE APPEARED ABOUT 10-15 FT ABOVE US AND SLIGHT TO THE R OF THE RWY CTRLINE. HE LANDED IN FRONT OF US ABOUT 50-75 FT AS MY PLT CHOPPED PWR AND APPLIED BRAKES. (LATER WE FOUND IT WAS A TRANSIENT AIRPLANE THAT PICKED UP AN UNKNOWN PAX AND DEPARTED. NONE OF THE LCLS COULD IDENT THE AIRPLANE). I BELIEVE THE NORDO BIPLANE MADE A HOTDOG; LOW; CLOSE-IN APCH; WITHOUT ANY S-TURNS ON FINAL. IF HE HAD MADE A NORMAL APCH; AT LEAST ONE OF US WOULD HAVE SEEN HIM BECAUSE OF OUR EXCELLENT; LOW-WING VISIBILITY. WE HAD MULTIPLE DISTRS; BUT I KNOW WE BOTH LOOKED PROPERLY FOR TFC BEFORE WE ENTERED RWY ENVIRONMENT. I MADE THE PROPER RADIO CALLS AND DID NOT HEAR ANY CONFLICTING TFC CALLS. IN THE FUTURE; IF I'M PIC; I'LL DO A 360 DEG (TO LOOK FOR TFC) IF I'M DELAYED ON THE RWY (A LA LAX); BUT IN THIS CASE; I STILL DON'T THINK IT WAS WARRANTED. I HOPE THAT IS THE CLOSEST I EVER COME TO ANOTHER ACFT!