Well, there's no way to install multiple copies of OmniFocus on your iPhone, and OmniFocus doesn't support having multiple sets of sync settings at the same time. (I'm not a coder, but that sure seems like it would get really hard, really fast.)
In any case, it's possible that we'll have features that will make this easier at some point in the future - having some sense of "my tasks" vs. "shared tasks" is one of the things we've thought about. That won't help you in the short or medium term, though.
If you watch our
Perspectives video, you could use that to enforce the work/home divide without actually having the tasks in two different databases.
That feature only exists on the Mac right now, so your phone would show tasks from both, though. I know we have requests to bring Perspectives to the phone; if that would help you, send email to the support ninjas; they can attach your email to that item in our development database. (You can do so from the help menu in OmniFocus on your Mac, or from the Settings screen in the app on your phone.)
If that solution doesn't work for you, the only other thing i can think of would be to use an iPhone and an iPod Touch rather than two iPhones...