AT APRX 0612 EST, AN EASTERN AIRLINE CAPT (OWNER OF PIPER PA-23, N2185P) DEPARTED A RWY NEAR HIS HOME IN VFR CONDS TO COMMUTE TO WORK AT TAMPA, FL. SHORTLY AFTER TAKEOFF, HE CONTACTED A FSS & UPDATED THE WX INFO HE HAD OBTAINED ON THE PREVIOUS EVENING. AT THAT TIME, THE CURRENT TAMPA WX WAS, IN PART: INDEF CEILING, ZERO OBSCD, VIS 1/16 MI WITH FOG, RVR FOR RWY 36L WAS 1000' TO 1600'. BEFORE N2185P ARRIVED, 2 OTR FLTS HAD DIVERTED FM TAMPA DUE TO THE WX BEING BELOW MINS. DRG ARRIVAL, THE PLT OF N2185P MADE 2 ILS APCHS TO LND. DRG HIS 1ST ATMT, HE MADE A MISSED APCH & ELECTED TO 'GO BACK & TRY IT AGAIN.' WHEN CLRD FOR THE 2ND ILS, THE RVR WAS 600' IN THE TOUCHDOWN AREA & 1000' AT MIDFIELD. SUBSEQUENTLY, THEPA-23 TOUCHED DWN ON A PARALLEL TAXIWAY & COLLIDED WITH BOEING 727, N4743, WHICH WAS BEING TAXIED FOR TAKEOFF. THE 727 CREW DID NOT SEE THE PIPER UNTIL IT WAS APRX 500' AWAY. THE CAPT OF THE BOEING STEERED RGT, BUT WAS UNABLE TO AVOID A COLLISION. THE DECISION HEIGHT (DH) & MIN RVR FOR THE APCH WERE 200' & 1800', RESPECTIVELY, FOR CATEGORY A, B & C ACFT.