A discretionary trust is probably the way to go. Accountants and lawyers can set them up and you should use an expert because there are so many issues to consider.

If starting a business asset protection should also be a major concern.

Yes – can claim interest on the loan and Yes can claim depreciation

what are you trying to achieve?

Depending on what you want to do and why you could do it 2 ways. One is as a bare trustee. Other is just gift the money to them and have them by it themselves.

There are heaps of issues involved such as tax, stamp duty, loans etc

Teds, I may have misunderstood your post. So you are not unconditional, but another buyer is? So you would have less risk than i imagned, but you have an offer in there without seeking legal advice on it. If your offer is accepted you will be locked in. You should really show what you have signed to a lawyer now to see if there are any issues. If there are you can withdraw your offer and resubmit with changes.

Thats a large risk. No lawyer and unconditional now!

Why not pay off the home loan sooner and buy an investment property? Not mutually exclusive.

You're right in that you cannot borrow from yourself. You can borrow from third parties and the loan would generally be deductible and you could refinance it with another lender. Just need to make sure you have a written loan agreement and set it up properly.

Perhaps a discretionary trust would be the way to go rather than family.

In the past I have had problems with CBA when trying to sign loan agreements with a power of attorney – they refused to accept them because of privacy concerns – the attorney would see what the donor's financial situation was and also potential problems later proving that the borrower did not understand their obligations. Under the Power of Attorney Act an attorney can bind the donor and basically enter into any agreement that they can legall enter (subject to any restrictions in the deed) but there are no requirements for others to accept them.

In the past I have had luck with ANZ and Westpac.

It may be able to be done, but as trustee of your smsf you would be not acting in the best interest of your fund by putting all of its cash into the one investment. Consider carefully if this is the case.

It may also be possible to join with a spouse or others to pool your super money together. Many issues here to though.