If a financial organization provides "greater than 100% loan-to-value
property loan" then in this situation 'what' is the 'security' for the
above mentioned loan-to-value loan  besides upto  100% loan-to-value 
mortgage  loan?

typically, the part of the loan over the value of the house is
unsecured, like a credit card.

the partially-secured nature of the loan generally means that the
interest rate won't be as bad as the worst credit card rates, but the
interest rates are typically far above what you would pay with a
conventional mortage.

I suppose from the lender's point of view, the fact that the house
exists at all indicates the borrower must have had enough money to buy
it at one point, and is therefore a better risk than if the house
didn't exist at all.

I hope this helps you out!

thanks,
David


there are many web sites which discuss the risks of high LTV loans:
see, for example:

http://www.in.gov/dfi/consumer/pdfs/hltvloans.pdf 

http://www.bankrate.com/brm/green/loan/loan3h.asp?prodtype=loan

search terms: high loan-to-value