if you have done real estate website using LAMP then your at the right place.
1. it should use mysql, php, apache
2. real estate web site functionality
3. add remove tables or update field names, restrict sql search query to table defined by date, persons name etc...
4. login based on one ip, only one user allowed to login
5. 3 failed attemps and user get locked out only admin can unlock account
6. you should use SEO to optimize the site so its on top websites..
7. user managt. interface.....
8. able to integrate social networking site profile like twitter,
9. checkout cart you can use paypal checkout cart.
10. provide user stats.
if you have a portfolio of real estate website contact me, i will also provide site which you can use to mirror data ...