if you are willing to drive, a very unknown beach we kite at is Merriks beach, just north of Pt Leo. Anything from SSW - S - SE - E - ENE is perfect as the wind is very "full", without any holes or huge lulls. Then there's Rye, McRae and Dromana for the winds with Northerly in them. Southerly, especially SW seems to be good along the LongBeach area (Seaford to Aspendale).
i am only a n00b, so i dont know alot of spots, just the ones i go to that are uncrowded so i dont kill ppl with my kite

Just a word of warning with Merriks, there are rocks in the shallows about 15-20m out, so be careful of these when u first launch.
Good luck finding a spot.