Adman, for a tech-savvy user, it certainly will work at home. Several of the "residential VOIP" providers support CP7940 and 7960s.
One of the benefits of the system we're using is that "take your phone home" IS supported, relatively seamlessly. Naturally, we'd be able to track a disappearing phone hooking into our system remotely, but as VOIP continues to expand the ubiquitous device will become more common.