Q: why is running a cable across the house not an option?
it's not length, since 30m should be enough for most mcmansions.
it's not cost, since cables are fairly cheap. Cheapest option there is.
you run along wall edges, taking the long way if you have to. When crossing open areas, you lay a rubber cable protector over the top (or a strip of carpet with a gutter cut out underneath), to stop tripping and make it look nice.