If you don't mind going up and downstairs, and you're confident that the basement won't flood again, you could put most of your quilting stuff in the basement and use the upstairs one for the stash you're not using on current projects. Leave space downstairs for that future longarm - but spread things around so no one else thinks THEY can use it!
I agree with the others who said make an OBVIOUS path through your things to go to DH's room. No excuses for 'touching' your stuff!