Hello Buyer,
I am pleased to inform you that I have recently worked on something very similar to www.realmast.com.
Please check out the site that I created for a real Estate Agency at www.tomandsally.com. It is created using vb.net and is completely database driven. I am currently making changes to this site to enable the client with a easy to use Content Management System so they can add not only new real estate properties and agents etc but new pictures, text, color etc. Its a templates driven site that uses Database to display text, graphics and all the required vital information. Also please take a look at the alexandriaapts.com. It is a similar system that uses ASP to derive its functionality.
If you plan on developing some site like this to thrive an upcoming business or make an established business more successful, please contact me as soon as possible to address you urgent requirement.
Thank You.