I've had an ADCO cover for my rv for the last 5 years. (It also came with a bag which are useless in my opinion)
I've used their alternative "secret ADCO method" for storage which would work for any cover.
To remove the cover from the RV:
1. Roll a larger clean plastic trash container with wheels to the REAR of your RV.
2. Feed the REAR of the cover into the bottom of the container and continue stuffing the cover into the container.
3. Place the lid on the container and roll it away to corner of your garage until the next time you need to cover your RV and it's all ready to go.
4. To cover your RV now, just roll the container again to the REAR of your RV. The front of the RV cover will be at the top of the container. Pull the cover up the rear of the RV and forward along the roof until it`s all on top and then drop the sides.
I`ve used this idea since I had my cover and it works great and cover is stored protected when in container.
Even if the made a vacuum bag big enough I`d be hesitant to store in like that.