If you are going to spend that sort of money on a jetski (which personally i despise as 80% of people that i have interacted with on the water with jetski's are complete aqua bogans - just tear up the water and drive dangerously close to other water users), why not get a boat?
We have a solid ski/wakeboarding boat for well under those $$$ - its an older model, but is still 270HP, can fit 7 people and puts up a wake the size of more recent boats that cost $70 000 plus. Very quiet inside, and the wake flattens out at faster ski speeds for slalom skiiing.
I just think for a family that a boat is a much much better option as everyone can enjoy it.
This is our boat below - we have about another 5 families that regularly join us for days on the river. Its an american built Ski Nautique and way better quality build than any Aussie boats
We have terrible problems in Vic with jet ski operators.
I agree with you - a family boat which you and the family can all enjoy together without having a huge impact on those around you... 
Have to agree with the aqua bogan tag.
We own some beachfront property over on the west coast of SA where we go to get away from it all. Unfortunately, one group of nearby property owners down the road choose to rent out their place to a group of these aqua boges (weekly rent is cheap during peak summer period when you divide it by a dozen plus of these "mouth breathers" to a house).
Every year without fail we are awoken to the sound of jetskis from these idiots flying across the harbour cove in front of our property and every year we call the marine harbour patrol who issue them with fines for exceeding the 4 knot speed limit within the cove.
Not only are they a safety hazard, but they scare away all the marine life in the area for the next few days leaving shore based or tinny based fishing an impossibility.
