GitHub User: maxwell
Heroku PG databases do support schemas, although I have been through it a bit with some of the tech there, and a couple of their internal tools (for example, pg:dump) for some reason slow down to unreasonable speeds, so YMMV. If you have a few large clients, I assume it would be fine, but I think lots of smaller clients (according to Heroku, lots being more ~ 20), you would be better off using the join method.
Yay! I wrote that Devise wiki page last week, I am glad somebody found it :)
worth pointing out that Diaspora has a bunch of jasmine specs if you want more examples!