What is the integer value the gives a broadcast receiver the highest priority?
<intent-filter android:priority="1">
<action android:name="android.provider.Telephony.SMS_RECEIVED" />
</intent-filter>
Well, according to the documentation
"The value must be an integer, such as "100". Higher numbers have a higher priority."
So I'm guessing that any integer value is valid. And the highest priority possible would be the maximum integer that android allows, which is (2^31 - 1).
EDIT
The documentation has been updated, and it now explicitly states which priority values may be used by applications. The documentation now says
SYSTEM_HIGH_PRIORITY (1000): Applications should never use filters with this or higher priorities. SYSTEM_LOW_PRIORITY (-1000): Applications should never use filters with this or lower priorities.
Implying that your application is permitted to use integer priority levels between -999 and 999.