One of the biggest bugbears about the generally-excellent Steam delivery service has been its complete failure to offer you an actual choice of where to install your games. Now this appears to have been solved in an upcoming beta patch, as noticed by sharp-eyed Redditors.
You’ll need to opt into the Steam beta to do it, and from there it’s a matter of changing some launch options and bringing up the service’s developer console to specify some alternative install locations manually. But once you do that, you’re all set to spread your Steam install across more than just one hard drive. Rock, Paper, Shotgun has a great guide on how to get it going — use at your own risk, naturally.
Hopefully this means that Steam is on the way to including this themselves, and in a manner that doesn’t require any sort of voodoo or jiggery-pokery. Keep an eye on the patch notes.
Source: Rock, Paper, Shotgun (Thanks, PalZer0)