How does one meaningfully measure maintainability?

Question

Context: I'm an enterprise developer in an all-MS shop.

Can anyone recommend a good way of objectively measuring maintainability of a piece of code or an application?

Why maintainability: I'm tired of "quality" metrics in my group revolving only around number of bugs and code coverage. Both metrics are easy to game, especially when you're not measuring maintainability. Shortsightedness and deadlines result in huge amounts of technical debt that never really get addressed.

Why the ability to measure objectively: I work in a big enterprise group. If you can't objectively measure it, you can't hold people accountable for it or make them get better at it. Subjective measurements either don't happen or don't happen consistently.

I'm looking at VS2010 code metrics, but I'm wondering if anyone has any other recommendations.