How about cornices above the doors that end just at the top of the molding so it looks like the window is larger and then use either Roman shades that are rolled up when you use the door or wooden or just regular darkening shades. I have mine hidden under the cornice in the daytime. I did put up sheers with grommets which slide so easily so I push them to the sides when the door is not in use.

You can buy magnetic curtain rods made just for this type of application. You can even buy magnetic mini blinds. They come with a hold down bracket for the bottom so that they don't bang around.

Here is a link that might be useful: Amazon magnetic curtain rods

I've been thinking about the cornice above the door; where the shade would just tuck up underneath. It would have to be light-weight, due to the length (Roman shade good for that). I've not been able to find images of this application anywhere, I'm surprised as surely others have run across this issue.

The magnetic rods are only good for really light fabric, as I've seen. I think blackout material would weight it down.

Thanks!

Could you post a picture of the wall with the door?

Any reason why you can't put in a drapery rod and drapes with a blackout liner? As long as there is room for the drapes to stack on the wall beyond the door, this would work fine.

And, how often do you use the door? My guess is that most people walk outside through a door in the living area.

Terriks suggested the magnetic rod, which is certainly one good idea.

You could also look at Command adhesive hooks to rest the rod on. We did this on my in-laws back door, hung drapery and worked well.

A third alternative is to replace the insert with one that has the built-in blinds between the glass. Since you say this is a new door, perhaps you considered that option and chose not to do it, but I would check with the door mfg and see if they have the option, or purchase an after-market unit that is available at the home centers.

If uncovering the window is not an issue, I would also look at using heavy-duty velcro (marine velcro) and mounting that on the door, then hanging a roman-look fabric shade lined with blackout lining. That velcro is very strong, tho I am not sure it could hold an operating blind, but certainly one that remains in place would be fine.

Without seeing the room and the location of the door in the space, another choice could be to mount the rod high above the door and then stack back the curtains to one side during the day. But again, without seeing the space it is hard to know if that would work and look nice.

Let me just say one other thing. If this is your space, and your door, and you are ALWAYS going to need to have the door covered, then I guess I don't see what the real problem would be with drilling into the door. It's not like a month from now you are going to decide you don't need the room dark when you sleep, or that you are moving. Pick a window treatment style that could be changed if you decide to change out your decor down the line - curtain rods that could take all kinds of window treatments would likely be best.

I'm not sure how to get a "window treatment" for it that will allow me to be flexible with the direct light that comes in -- I'm a night owl, so I like BLACKOUT until I am ready to get up in the morning.

Maybe use a blackout curtain, cut to length for the window, that you can tie back?

It seems like drilling holes into the new metal door is a last resort. I also don't like blinds that bang against the door when you move it (sloppy).

There are magnetic rods (think I saw that mentioned already). There are also tension rods, if there's enough trim around the window (you mentioned 1/2" -- I'd think most of them out there can work in that space). If your WTs are lightweight, you can also get adhesive curtain rods. As for blinds that bang, there's usually equipment included with blinds to secure them at the bottom to avoid this.