I presume that you are looking for horizontal venetian blinds. Any blind shop will fit them and they dont work out that expensive. As they fix them to the door, they fix them near the top so that when you pull them up they dont cover the glass and you can tilt them to block the light just the same as shutters. you can get them loads of widths of the slats and in multidues of colours, so thar you could pick something to match the door and it would look like shutters - the only disadvantage as I see it is that when you pull them up, you have a long cord to secure to keep it safe from kids and animals. I presume that your doors open in the way so this is the only way to go - if they open out the way, you can fit normal venetian blinds into the fram to cover the whole gap and you don't need t worry about the doors hitting them as they open.