I have an idea that may be good for one of you engineers.. How about for a trunk floor mat, in order to allow easy access to the footwell for storage you could add a hinge to the floor mat? Then assuming it is a rigid allweather mat that lays flat, take out the normal footwell cover and just put a handle or loop on the floor mat so we can lift the front half of the floor mat up due to the hinge to access the footwell.
Or if the footwell cover is needed, then have the little loop that you normally use to open the footwell attach to a hook under the floor mat and have a handle or loop on the floormat which would then lift both the front half of the floor mat (due to the hinge) and the footwell cover itself.
Or if the footwell cover is needed, then have the little loop that you normally use to open the footwell attach to a hook under the floor mat and have a handle or loop on the floormat which would then lift both the front half of the floor mat (due to the hinge) and the footwell cover itself.