Muslim units
No, I didn't mean segregated units and I know that no such units exist.
In would definitely be a bad idea if it appeared in any way contrived. If I were involved in recruiting I would certainly be pleased to see Muslim volunteers and I would think that the image of American Christian and Muslim soldiers fighting side by side would be a powerful image.
Actually, I have no idea how many Muslims are available or how willing they would be to enter the service. I do know that most college sports teams have several Muslim members and that is the picture that was in my mind.