What to do about outlets in the floor?

I just moved into a group house and it's lovely. But it's also old, and I'm trying to figure how to accomodate my furniture (enough for a whole apartment) in a bedroom and ensuite sunroom. A lot just had to go.

But this is made more difficult by the fact that almost all the outlets are embedded in the hardwood floors. I can't NOT have furniture on top of them, and I can't NOT have access to those outlets either.

In cursory web searches I've come across what seems to be called a "flat plug power strip liberator" (or something close to that) -- but even what they're calling a flat plug doesn't really look flat enough that I could put, say, my two-drawer filing cabinet on top of it.

Any ideas or solutions??

(Sorry the photo's not real clear, and not of the bedroom -- but the ones in the bedroom/sunroom are the same as the one that's slightly visible in this pic)