I wish you luck, but all the shells I have seen that had these goals in mind just kind of disappeared pretty quickly.
As far as maintaining a job at 75 - wouldn't you just be able to like use, level sync? Then only a couple of you, probably the officers, would be required to stay at 75 and you would have a bigger pool of people to choose from. The number of folks who will keep a "main" at 75 is probably a lot fewer than the people who already have\want to get their "main" to 99 but would be willing to play at level 75 and be a part of the shell.