It's to bad you refuse to accept using A/B switches. That would be your simplest solution. Add a powered sub-woofer with speaker-level inputs and you'd be all set.
Pity...
Oh, you certainly can fine multi-channel speaker that do music very well, but they aren't necessarily cheap or small. The way to find them is,when shopping, use music as your test source, not a movie soundtrack. If a speaker does music well, odds are 99.99/100 it will do HT at least as well.
Oh, and you might want to forgo using a subwoofer in the selection stage using music. A sub can be added at any time.