Why not just have your SME's on one staff... It's how the Marine Corps does it. We've got a group CO that's in charge of multiple T/M/S (and has multiple T/M/S SMEs on staff), and a Wing CG who has the same. There is no such thing as "Marine Medium Lift Wing Atlantic"
We've got more than our share of fat that needs to be shed. You used the MAG as an example; so will I. Does the MAG HQ need to be as big as it is? Does every squadron function need to be replicated at MAG? (Or, for that matter, does every MAG function need to be replicated at the squadron?) This is not WWII, Korea, or Vietnam. We simply do not fight as MAGs anymore. They are just another layer of bureaucracy that could/should be looked at for possible reductions. In fact, do we even need standing MAGs anymore? Can a slightly larger Wing staff, with "site manager"-like staffs at each location, take the place of our standing MAGs? We pride ourselves in being task-organized. If there's a need for a MAG somewhere, we can always stand one up where necessary (MAG-40, for example). Bottom line is that there are plenty of ways to make reductions and keep an effective fighting force.
The suggestions by Secretary Gates will certainly draw a lot of criticism, but it appears he's actually trying to save us from the inevitable post-war draw-downs. Those of us on active duty in the mid-90s know what it was like in a post-Desert Storm military. In fact, it can be argued that we spent the better part of the 2000s trying to recover from the neglect of the 1990s. It is something that those who came in post-2001 will never understand.
Case-in-point: Our equipment. When I came in (mid-90s), we were using Vietnam-era flak jackets, field jackets, sleeping bags, and ALICE packs. OIF kicks of, and all of a sudden the "GWOT Money" kicks in. We're suddenly bombarded with ILBEs, multiple flak jackets, Gore-tex EVERYTHING, and high-speed sleeping bags. Our gear is exponentially better than it was even a half-decade ago. However, there is already griping, just a few years later, that we need "new" flaks, blankets, packs, etc. Well, if we want to continue to fund good equipment for our Marines, we need to make sacrifices elsewhere...lest we use the same gear for the next quarter century, and then play catch-up - again - when the stuff hits the fan once more.