First Home Owners Group Pty Ltd (which is separate company of mine) of which i am 1 of the 3 Directors is Qld largest provider of instalment contract finance.
We have an arrangment at credit level with 2 of the Big 5 Banks who have funded all of these deals for the last 10 years. They are happy that we show the instalment receipts as gross income and of course the loan as a liability assessed at their qualifying rate.
It will depend on what mark up you put on the property and the rate you charge the potential wrappee as to whether it increases your capacity to borrow.
Unfortunately on a smaller scale with the odd 3/4 deals you will find most lenders shy away from accepting the business and therefore are not prepared to take the instalment income.