I have seen some snazzy ones on the carousel idea, but the door sits at an angle across the corner and the whole door rotates, those are quite wide I think, so I am not sure if you have room to have two of those and the sink unit in the middle. My mums kitchen is U shaped, the window runs down one wall, but her sink still sits on the end wall and tbh I don't think it really matters - you probably spend more time standing at the food preparation area than at the sink, so you would probably make better use of the light, you would need to consider where your plug points would be for your small appliances - the benifit of the sink under the window is that you dont normally need to plug anything in there.