Years ago, when I costumed LITTLE MARY SUNSHINE, I needed a bunch of red military uniform coats. I found a good shirt pattern -- with a collar set onto a neck band -- and made it without the collar portion. The neck band was just wide enough for a piece of trim to make it look a little military. I think your project will work just fine. Watch out when you remove the collar, though, as some blouses have a 1/16" difference between the outside and inside collar bands to make it stand more upright.