Well, there's bacially that, using another sound card, like the GameSurround Muse, which has a knob on the tob, or going with an expensive external sound solution, like the Audigy2 ZS Platinum, Extigy, etc. that have remotes.
External PC parts do cost too much...I won't disagree there. But they seem to universally cost too much, rather than it just being the good products.