Careful on that ice, Phil...
Hey, kids - It's Slippery Slope Time!
Were I homeboy security, yes I would profile Islamic converts for higher priority scrutiny.
[ *grin* at "homeboy security"]
OK... how do you find out who's a convert? Bully the mosques into giving you their records, with threats of Federal prosecution? (If you saw that recent episode of "Law & Order" with reference to Santoria, you'll know what I mean...) Get warrants to sieze the records of every mosque in the country? How about some "reverse profiling": surveillance of all the mosques, and investigation of all non-Arab-looking people who go there?
Or maybe you'll rely on the converts' friends, neighbors and co-workers to inform on them.