These are all 1999 or 2000 ET models due to clear indicators. Let's make them 1999 since we can't see if they're ET2 (99) or ET4 (00):
http://imcdb.org/vehicle_164733-Piaggio-Vespa.html
http://imcdb.org/vehicle_320305-Piaggio-Vespa.html
http://imcdb.org/vehicle_338916-Piaggio-Vespa.html
http://imcdb.org/vehicle_671959-Piaggio-Vespa.html
http://imcdb.org/vehicle_91392-Piaggio-Vespa-1997.html
http://imcdb.org/vehicle_318607-Piaggio-Vespa.html
I found a few others, but they had custom paint etc., so I wasn't sure.