As you mention, 'jD uses the active layout', there’s seems to be noway to use the nonactive layouts.
Making it possible to also be able to select non default is a great opportunity to fully use the power of the template functionality.
For example, I want to do this:
menuitem 1, show a category in default layout (named: layout1)
menuitem 2, show another category in a non default layout (named: layout2)
At one menuitem want to I want to use columns, show the category with other fields and remove the up navigation button etc.