I moved this to the image gallery so I could attach a picture.

That is a large paisley print. I don't think it lends itself to what you are thinking about doing, but I agree it doesn't look good below the transom either.

It's best to post your picture right in your post when you want advice. Here it is:

Your idea of adding some more of the same fabric with trim is a good one.

Soory but I don't like the look of added on material. Trust me, I know how hard it is to find something that you like, but I think there must be another paisley to suit your style.
Since you are looking at simple panels, you might buy fabric and have them made by a taylor.

I have to disagree with ellendi. I have seen drapes that were designed with a wide border and look fantastic. There was another recent thread here on the same subject.

Here's a pictre of some ready made drapes with wide bands at top and bottom:

Here is a link that might be useful: Too short drapes thread