I would suggest your plumber links the hot and cold fill pipes to the supply UNDER the sink - this gets rid of unsightly pipes and while he's there get him to move the taps to the L side of sink. I would then create a broad drop down counter top to create a place to sort your laundry ready for hanging out to dry or to fold ready for ironing This drop down counter top to be hinged to R side of washing machine and ensuring the taps are not impeded. If you can't do the drop down version then create a free standing top made out of a piece of MDF/laminated board to put over the sink and washing machine for clothes sorting & folding. This free standing top can 'live' at the side of the washing machine when not needed. I would then put shelves above the folded back counter top to store washing powder and sundries. I would store the washing powder etc in colourful or white boxes to keep the place looking tidy and uniform. Handles on the boxes for ease of access. Oh I do love organising - can I pop round and do this for you? Hope all goes well with the changes.

~$400 including expedited shipping. My GC just had his regular countertop guy do them, which wasn't great.... he had trouble making clean cuts. If I were going to do it again I would have pressed for someone with expertise to cut them. You can see in the image that the facing is not made of the stone peak, because too much was broken during the cutting to make the mitered edge. I'm a little bummed, but mostly pleased with the surface (which is the important part) thus far.

Wow, that was awesome Mark, thanks for that and everyone else. I thought about the desk facing the other way actually, to avoid feeling enclosed I do have really great views there so I thought about a small couch and maybe a bookshelf on the back, but having the dining table in front is probably not the best either.... complicated :( Here are a couple more pics, today was a beautiful day so I managed to get more of the views

Kind of funny really how many people would feel exposed and would not want to use the bathroom. The more I think about it, it's a bit like a public restroom with stalls (as stall walls rarely go to the ceiling or floor and have the added issues of gaps between the wall panels and doors -- which thankfully we won't have!). Regarding the humidity control issue, I should have clarified this is only for a toilet and small hand basin (not a full bathroom with shower). The main room on the other side of the proposed toilet is our dog whelping room where we will have young litters of puppies (when we have them). Further down the hall, removed from this room, is our training room where there are likely to be other visitors but the proposed bathroom would be quite removed from that area. It would be wonderful to find more windows like the ones that are up near the ceiling! That would certainly solve the issue. I'll have to scour the demolition/restoration places.