IMO i would look at developing this (dependent on your time, budget and inclination) as I can see this being a great site, bringing in a very nice revenue if done properly with good content, good website etc
A good pre launch campaign is also really important - the below gave me some really good ideas.
You could generate a very nice income with mortgage provider partnerships, go to them direct and they will pay a percentage of any completed deals at the back end, also from the affiliate side you can make money at the front end. You then have the option of ad's as and when the site starts getting enough traffic
I am having a site built (way behind schedule) for a commercial mortgage/lending site and will be implementing the above partnership structures.