I just stumbled across Android test size annotations and think it would help separate the JUnit integration tests which contact external controllers (which would be annotated with @LargeTest) from other JUnit tests:

http://googletesting.blogspot.com/2010/12/test-sizes.html

http://developer.android.com/guide/developing/testing/testing_otheride.html has some intructions for the am instrument command to run tests by size.

This may take some fiddling with the auto-generated ant build script to get working smoothly, but could conceivably save a good bit of time.