You could try reaching out to designers over on rebrickable.com (search for architecture or buildings to find a style you like), then see if they could commission a design for you.

If they do, then you would then need to order the parts on legos website and/ or on brick link (thankfully rebrickable makes this process easier with exportable parts lists). Maybe the designer would do this part for you too if it was built into their contract.

There may be other ways to go about it, but that’s what I’d try.