The UDID is a SHA1 of a few other identifiers, such as the MAC and Serial #. What Apple should just do is include the base Application bundle prefix (whatever the thing is that is used to give applications shared keychain access) into the mix as a per-application-suite salt.
I completely agree. You should file an enhancement request.
There are so few legitimate reasons to have access to the UDID in the first place - I was surprised Apple even allowed it. An app- or app suite-specific identifier, though, could be very useful (and would work perfectly as a replacement for a number of the cases about which people are complaining).
