I change between screen layouts quite often, made Pie for that.
Maybe someone else will find use in that also.
You need Blender with pie menus support(you can get one from daily builds), also as it stands now Pie menus are limited to 8 items max, I personally always have less layouts than that.
Did you mean to ask if I would create default keybindings/hotkeys for this?
I wouldn’t want addon like that to take over some key that author thought would be good, i think it’s better if everyone just assigns whatever they feel like.
Here you have template for normal menu if that’s what you wanted. Adding that to specialmenu under W doesn’t make sense as you would be able to use it only in 3d view also I think you can’t call Menus from dynamic spacebar.