JV with land owner – Advice needed!

Hi guys,

I've found a land owner(in Sydney) who is willing to do a JV with myself and a builder. He provides the land and the builder and I take care of the development. We then pay him at the end. Possibly all in cash, but possibly with stock (a villa) and some cash.

But the builder says he's seen arrangements like this turn sour in the past, as because we don't own the land, getting finance through out the project can be difficult. This is because when you require extra funds etc, you need the involvement of the land owner. So the builder will only do the project if we own the land outright.

Now.. if the vendor is willing, is there a way to get around this?? can we buy the land off the vendor at a nominal price ( say $100,000) almost as a deposit, with a contract stipulating that the remainder of the funds will be paid later. This way, we save a heap on interest payments and still maintain control of the land. Of course this is if the vendor is willing.

My question is – What are the possible problems that can arise with attempting this? 
How does the taxation department view it?
Can you actually sell a property that far below market value?
Will we still be liable for the full amount of stamp duty on the property's " fair market value"
If we gave the vendor a Villa and cash at the end of the project. Would we pay GST on that villa? as we've created a "new dwelling" in the eyes on the tax man, but not actually sold it?
Is there another way to do this?? can the vendor sign a form that gives us a virtual power of attorney( or something equivalent) so we don't need to sign a form every time we need more money for the development??

Sorry to bombard you all! But I'm a bit out of my depth here and would appreciate any advice you can offer.

Cheers

Naremburn.