This already exists (community) but it would be cool to formalize it a bit more.
Proteges get a list of issues based on the 'level' they choose. They get a mentor to help them try and solve that issue.
Mentors would volunteer to help new contributors. and choose a 'level' they were willing to support.
Proteges would become active contributors quicker and hopefully become mentors themselves.
By using the mentoring system per issue, Mentors wouldn't get burnt out and proteges wouldn't become too reliant on one person.
I think it is very important to focus on all levels of contributors. Docs, New people, Intermediate programmers etc.