These use one screw to mount and are as close to flush mount as you can get without cutting a hole in the floor. I can still slide things over them easily and sleep on top of them with my 2" foam pad without feeling them.
Funny, those are the same ones I installed underneath the mattress in my teardrop, so I could secure gear inside my trailer getting to and from my camp spots. They've worked well for me.
SMB-less as of 02/04/2012. Our savings account is richer, but our adventures are poorer.