One has to realize what Crestron (or others) have to do to get the metadata from the Apple devices in order to display them on various controllers throughout the home (remotes and touchpanels). They also have to displayed for each different display resolution. It's not as simple as docking your iPhone and have at it.
Crestron is as up to date as any company when it comes to Apple and iOS (including the brand new iOS5) related products but they also have to control, tvs, cd players, vcrs, dvd players, blu-ray players, Apple tvs, projectors, screens, thermostats, drapes, lights, alarm systems, pools and spas and anything else that comes to mind when it comes to control.
Crestron has mobile apps to control of the system from your Apple device, eControl for your mac, iServer for docking of your ipod which syncs to your iTunes and other Apple related software and hardware.http://www.crestron.com/products/app..._ipad_control/
With the dizzing array of options of harware, imagine what the options for programming can be. It takes a good programmer to make very complicated things seamlessly talk to one another and in such a way that is easy to use, and understand to the homeowner and also guests.
This is why most integrators will only use the products they spec because having a reliable system is just as important. A lot of time, sweat and frustration have lead several of them to use systems they design and spec because they don't want to be married to you and your system constantly fixing things that should never have been an issue in the first place. You also don't want to be calling them all the time because that means your system is down and not working correctly.
Having a system that doesn't have to do anything else is easy, just see Sonos, but these devices don't play with anything else.
Talk to the integrator whom you have been in communication with and ask if they have anything less expensive for you. It may not do what Crestron is capable of, or be as easy to use, but that is what you will have to compromise.