HotFix: iPhone 3GS and iPhone 4 supports full device encryption (obviously not storage card). See:
http://developer.apple.com/library/ios/#featuredarticles/FA_Exchange_ActiveSync_and_iOS4_Devices/Introduction/Introduction.html#//apple_ref/doc/uid/TP40010175
developer.apple.com/.../ios
JRVA: iPhone implements CAS redirection I believe. I have not tested a scenario like yours, but I tested going from 2007 to 2010 where I had different CAS servers. The iPhone connected to the 2007 CAS, received a status 451 (in the FolderSync response) with
the new fqdn. Switched over without a problem. Android however - no go...
That being said I think this is a good idea. The problem as it is now regarding security policies is that Exchange Server only does a polite request for devices to implement the policies. When the device reports back that policies are implemented that's
not a guarantee that it will have actually implemented this. I have created a test utility for use on the desktop that will happily bypass all policies and report itself as fully compliant.