WH what? Yes that is Windows Home Server, now officially sanctioned in SBS networks (see here).
More than that! I can tell you, I have used WHS to backup an SBS itself. And even more than that, I can tell you that I have used a WHS to restore an SBS fully. Admittedly, it was a 4-user network and I relied on the offline storage of Exchange on the workstations to complete the e-mail restore, but within 10 hours I had an SBS server with 150Gb+ of data backup and running.
So even if you have a 75-user network and you want to backup 10 critical workstations, you have a tool. Want to back up 20? No problem, use 2 WHS’s in the network and so on.