Hi, I made a little enhancement: Forcing SSL on subpages. It's a checkbox next to the Force SSL that makes any page under the current to have SSL forced. It does not require the current page to be served by SSL - you'd have to check the standard box to do that.
So you could have
/cart/ <-- http ( Force SSL: [ ], for subpages: [X] )
/cart/checkout/ <-- https ( even when Force SSL: [ ], for subpages: [ ] )
It's a few lines only... I'll make a patch if you like.
Not wild about the label "for subpages" but propagate/inherit seemed too technical.