Good luck on the closing!
In case you have no luck on used 550 covers,
The OEM cover quality is especially good but the seamstress was backed up filling CampInn needs, the last I heard, a year or two ago when asking about a custom project...
Cary could say more...if they have one on the shelf or how long to get one new...for 550.
Otherwise:
I betcha a compact suv type cover, say Ford Bronco Sport or Toyota 4runner would work...
something cheap for temp use - $100+ new on Amazon.