Rear shell Open Space Cover?

Whenever I camp, I usually bring my bike on my bike rack mounted on the rear hitch of the TM. At night or when I leave the campsite for any length of time, I put the bike back in that same area - locked of course. It works out well because it's like a mini-carport and out of the elements.

Unfortunately my site at Disney these past few days was extremely lame. The view to the rear and literally within 30 feet was the public bathrooms. To top it off, I was in the partial hook-up area meaning that there was a majority of tent campers downing six packs and using the bathroom at all hours. It also meant that every kid hopped up on holiday candy who didn't get that bike for Christmas would clearly see mine under the rear bed slide-out when entering and exiting the bathroom - a prospect I didn't find comforting but I digress. I ended up locking the bike in my truck bed out of sight under the bed cover. It was a bit of a pain in the nether regions to say the least.

Anyway, now that I'm in my third paragraph and likely offended everyone with kids or grandkids, here is my question: I've seen covers at CampingWorld that are made for enclosing the open space under the hitch area on fifth wheels and was wondering if someone has rigged up something similar for the rear space on the TM? If I had some sort of way to block up the three sides but still allow easy access, I would have felt a lot better about leaving my bike, along with my grill and assorted other camping supplies there when not in use.

Thanks!
Dano

(obviously still recovering from having my favorite bike stolen 40 years ago)