that website is written in ASPX which most highly complex sorting websites use and are far more expensive to create and run.
i think you are looking for a customer job if you want it in PHP, or an out of the box THEN a custom script.
i'm doing one right now which has over 1 million possible variables so if you want to know my programmer PM me and i will feed you his details.
just to let you know what i am doing, i've purchased a template shopping cart which i have already used, got some guys designing it for me homepage and cart , and then got this programmer to do the variables in the middle.
method= grab the right people for their skills and combine them as mostly nobody can do it all, they will always do somethign good and the other half-arsed.
tim