Looks good. Although I'd rename the "member of Group:Bob" to "belongs
User:Bob", so you would have:
User:BobBot - belongs to User:Bob
User:Bob (testing) - belongs to User:Bob
User:Bob (vector skin) - belongs to User:Bob
Although this opens the can of accounts with different names on several
User:BobBot may belong to User:Bob everywhere but in wikis Foo, Bar and
Baz, where Bob username was taken and he is known as 'Bob2'.
Showing that "BobBot is of Bob" may be a bit confusing as in that wiki
Bob is a different guy (even if coherent due to usage of sul usernames).
It's not a problem to have sul Bob2 as belonging to Bob, but the local
Bob may belong to global "Bob Smith". And if we start user groups, the
Bob Smiths out there will ask for them to be recognised.
Maybe there could be local accounts attached to user groups separatedly
from sul ones.