You could get kitchen door panels and attach them to an existing door.
However since there are no other cabinets in that same wall I am not sure this idea blends them in. I think making the door the same as the ball will hide it better. Either a conventional door painted the same colour as the wall or perhaps a pocket door.

Just remember you will probably be approaching this room with at least one basket of dirty laundry on your hip and probably a few mouldy mugs and rubbish from kids rooms too that you found while you were up there hunting for stinky laundry - make access as easy as possible - personally I'd configure the laundry room so it's accessed by hall then I wouldn't need a separate sink in there as I could use the loo basin if I needed to rinse something - that way I'd get more folding and sorting space in the laundry for all the piles for each person - keeps lost socks out of the kitchen too !!

I can perfectly understand that you don't want an additional door off the hall, and do you really want to approach the utility with washing etc, through a hall anyway? I just wonder why you want to make the door disappear, when its not on a wall with units? If it were, it might be easy to paint it/finish it similar to cabinets, but in the middle of the wall it will stand out anyway, whatever you do. To my mind, it might be better to just put an ordinary door in there, similar to other interior ones or glass paneled if you wan the light. If you are going to do it out with similar units to kitchen, it will flow in any case, if you can see them. Several friends have done this lately and it looks fine and the continuity through the glass paneled door just seems to make the kitchen appear even larger and lighter.

How about putting a swing door there, with no frame,no handles and painted same colour as kitchen then it should blend right in