Good product idea.

But what sort of user accounts are you talking about? LDAP or any arbitrary account? And always DBI? Via HTTP as well?

Especially I don't see "create account" is a generic job. Consider a Human Resources app. Creating an account means you also have to indicate who is his superior and who are his subordinates. But in order to do that the superior and the subordinates must be already in the system. Hence, "create account" is a recursive process in this case.

Obviously, I'm just not sure about the scope of your application and your problem boundary.