Ask HN: How should I make a point-to-point wireless home system?

This is a problem I think a lot of people have, including some smart hackers I know:

Your internet connection is at location X, and you want it at location Y. Wifi router at X and receiver at Y is okay for some applications, but the signal can get week if you're passing through lots of walls or floors. Also, if you're, say, streaming to an X-Box or a desktop PC used for gaming or streaming movies, a hit in speed is really noticeable.

Using a hard wire is great, but hard. Who wants to dig into walls or have lots of wires around?

Setting up wireless routers to act like repeaters or access points seems arcane, with questionable benefits.

So I thought I'd ask the smart folks here: how should I do this? If I really just want the X to Y speed maximized, is there good specialty hardware for this? Any hacks to take off the cap on broadcast strength on an easily available router?

[edits: - Ethernet over power is horrible in my experience. I don't even think there is a connection between the two spots

- Laying down line is untenable currently because it is a rental, and the situation is dire: separate back office (converted garage) to a living room in the house. I won't dig into concrete and most certainly won't drape wires.

- Why isn't this just a product? Two routers with directional antennae + N repeaters long the route? ]