Looks good. Although I'd rename the "member of Group:Bob" to "belongs to User:Bob", so you would have: User:Bob 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 wikis. 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.