Yeah, I don't think there's anything for line level, at least not that I've seen. There are (were?) a couple of products to send signals from a receiver to speakers (usually surround speakers) wirelessly, but it used its own integrated amplifier. I suppose you could convert it back to line level and then amp it, but it would be such a kludge that I can't think that sound quality wouldn't take a big hit.
I'm curious to see a setup that would need the amp placed somewhere else. Usually an amp is with the other components and speaker wires are run to whereever you need them.
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