Bill's OEM tonneau definitely DOES cover the entire cabin (I have one for the NB). It does require the snaps be added to the bases of the outside mirrors and the tenax-type posts at the base of the windshield - I would imagine those would be included with the OEM kit.
Great time of year to use a tonneau if you're a solo driver! Get's a lot of attention for being so retro looking. Just make sure the tonneau is warm and pliable before you try to put it on for the first time. I had to heat mine in the oven (wrapped in an old kids blanket) for an hour on the "keep warm" setting so it would give enough to get all snaps engaged. Another tip is to first put the passenger all the way forward, then fully recline the seat back. You can then adjust the seat position after the tonneau's on to fill the intended cavity in the cover.