Rebuild a booking system in PHP ( development only )

We require a custom booking system made using core php. It must be very secure & written very well with clean code and good indentations for future reference and help. You must use upto date technology for this, so that it should not get outdated for over atleast next 10-15 years. Its a basic software running on windows 2000 server with some good logic around. More details will be provided to the right candidate who will write "yes-read" before start of his/her quote. So Only Professional developers apply to this. Cheers!! Thanks