Membership Plug-in: Creating an additional membership class

We are using the Membership Plug-in, and we are finding ourselves need to create two different membership classes. (An example of this is regular members and a class of "Vendors," that will not have the standard membership classes that regular members will have but a completely different set of membership rules.)

For example:
Logged out user -> Unverified member -> Verified member
Logged out user -> Unverified vendor -> Verified vendor

What is the best way to implement this extra membership class? Is there any best practices that can be recommended?

- Ernie